Table of Contents

​

​

UNITED STATES

SECURITIES AND EXCHANGE COMMISSION

WASHINGTON, D.C. 20549

​

FORM 10-K

​

​

For the fiscal year ended December 31, 2022

​

OR

​

​

For the transition period from to

Commission File Number 001-37368

​

ADAPTIMMUNE THERAPEUTICS PLC

(Exact name of Registrant as specified in its charter)

​

​

Securities registered pursuant to Section 12(b) of the Act:

​

​

Securities registered pursuant to Section 12(g) of the Act:

None

​

Indicate by check mark if the registrant is a well-known seasoned issuer, as defined in Rule 405 of the Securities Act. ☐ Yes ☒ No

​

Indicate by check mark if the registrant is not required to file reports pursuant to Section 13 or Section 15(d) of the Act. ◻ Yes ⌧ No

​

Indicate by check mark whether the registrant (1) has filed all reports required to be filed by Section 13 or 15(d) of the Securities Exchange Act of 1934 during the preceding 12 months (or for such shorter period that the registrant was required to file such reports), and (2) has been subject to such filing requirements for the past 90 days. ⌧ Yes ◻ No

​

Indicate by check mark whether the registrant has submitted electronically every Interactive Data File required to be submitted pursuant to Rule 405 of Regulation S-T (§232.405 of this chapter) during the preceding 12 months (or for such shorter period that the registrant was required to submit and post such files). ⌧ Yes ◻ No

​

Indicate by check mark whether the registrant is a large accelerated filer, an accelerated filer, a non-accelerated filer, a smaller reporting company, or an emerging growth company. See the definitions of “large accelerated filer,” “accelerated filer,” “smaller reporting company,” and “emerging growth company” in Rule 12b-2 of the Exchange Act.

​

​

If an emerging growth company, indicate by check mark if the registrant has elected not to use the extended transition period for complying with any new or revised financial accounting standards provided pursuant to Section 13(a) of the Exchange Act. ☐

​

Indicate by check mark whether the registrant has filed a report on and attestation to its management’s assessment of the effectiveness of its internal control over financial reporting under Section 404(b) of the Sarbanes-Oxley Act (15 U.S.C. 7262(b)) by the registered public accounting firm that prepared or issued its audit report. ☒

​

If securities are registered pursuant to Section 12(b) of the Act, indicate by check mark whether the financial statements of the registrant included in the filing reflect the correction of an error to previously issued financial statements. ☐

​

Indicate by check mark whether any of those error corrections are restatements that required a recovery analysis of incentive-based compensation received by any of the registrant’s executive officers during the relevant recovery period pursuant to § 240.10D-1(b). ☐

​

Indicate by check mark whether the registrant is a shell company (as defined in Rule 12b-2 of the Act). ☐ Yes ☒ No

​

The aggregate market value of the voting and non-voting common equity held by non-affiliates of the registrant as of June 30, 2022, the last business day of the registrant’s most recently completed second fiscal quarter, was approximately $244,288,811.

​

As of March 3, 2023 the number of outstanding ordinary shares, par value £0.001 per share, of the registrant was 991,831,158.

​

DOCUMENTS INCORPORATED BY REFERENCE

Portions of the registrant’s definitive Proxy Statement for the 2023 Annual Meeting of Shareholders to be filed with the U.S. Securities and Exchange Commission pursuant to Regulation 14A not later than 120 days after the end of the fiscal year covered by this Annual Report on Form 10-K are incorporated by reference in Part III, Items 10-14 of this Annual Report on Form 10-K.

​

​

​

​

Table of Contents

Table of Contents

​

​

​

​

Table of Contents

GENERAL INFORMATION

In this Annual Report on Form 10-K (“Annual Report”), “Adaptimmune,” the “Group,” the “Company,” “we,” “us” and “our” refer to Adaptimmune Therapeutics plc and its consolidated subsidiaries, except where the context otherwise requires. “Adaptimmune” and “SPEAR” are registered trademarks of Adaptimmune.

CAUTIONARY NOTE REGARDING FORWARD-LOOKING STATEMENTS

This Annual Report contains forward-looking statements that involve risks and uncertainties, as well as assumptions that, if they never materialize or prove incorrect, could cause our results to differ materially from those expressed or implied by such forward-looking statements. We make such forward-looking statements pursuant to the safe harbor provisions of the Private Securities Litigation Reform Act of 1995 and other federal securities laws. All statements other than statements of historical facts contained in this Annual Report are forward-looking statements. In some cases, you can identify forward-looking statements by words such as “believe,” “may,” “will,” “estimate,” “continue,” “anticipate,” “intend,” “expect” or the negative of these words or other comparable terminology.

Any forward-looking statements in this Annual Report reflect our current views with respect to future events or to our future financial performance and involve known and unknown risks, uncertainties and other factors that may cause our actual results, performance or achievements to be materially different from any future results, performance or achievements expressed or implied by these forward-looking statements. Factors that may cause actual results to differ materially from current expectations include, among other things, those listed under Part I, Item 1A. Risk Factors and elsewhere in this Annual Report. Given these uncertainties, you should not place undue reliance on these forward-looking statements. Except as required by law, we assume no obligation to update or revise these forward-looking statements for any reason, even if new information becomes available in the future.

​

This Annual Report also contains estimates, projections and other information concerning our industry, our business, and the markets for certain diseases, including data regarding the estimated size of those markets, and the incidence and prevalence of certain medical conditions. Information that is based on estimates, forecasts, projections, market research or similar methodologies is inherently subject to uncertainties and actual events or circumstances may differ materially from events and circumstances reflected in this information. Unless otherwise expressly stated, we obtained this industry, business, market and other data from reports, research surveys, studies and similar data prepared by third parties, industry, medical and general publications, government data and similar sources.

​

​

​

​

Table of Contents

PART I

Item 1.   Business

Overview

We are a clinical-stage biopharmaceutical company focused on providing novel cell therapies to people with cancer. We are a leader in the development of T-cell therapies for solid tumors and have reported responses in multiple solid tumor indications.

​

Our proprietary platform enables us to identify cancer targets, find and develop cell therapy candidates active against those targets and produce therapeutic candidates for administration to patients. Our cell therapy candidates include genetically engineered T-cell receptors (“TCRs”) and HLA-independent TCRs (“HiTs”) where surface proteins are targeted independently of the peptide-HLA complex. Our cell therapies are currently manufactured on an autologous or per patient basis and we have a proprietary preclinical allogeneic platform for the development of “off the shelf” cell therapies.

​

Our MAGE-A4 cell therapy franchise includes T-cell therapy products targeting solid tumor indications in which the MAGE-A4 antigen is expressed, with responses seen in eight indications (head and neck, esophagogastric junction (“EGJ”), non-small cell lung cancer (NSCLC)-squamous, synovial sarcoma, melanoma, urothelial, ovarian and myxoid/round cell liposarcoma (MRCLS) indications). Filing of a Biologics License Application (BLA) for the lead product (afamitresgene autoleucel or “afami-cel”) in synovial sarcoma has been initiated with the U.S. Food and Drug Administration (“FDA”), with completion of the filing targeted for mid-2023.

​

Clinical programs with our MAGE-A4 targeted cell therapies are as follows:

​

​

​

​

Outside of the MAGE-A4 franchise, we have a preclinical program for T-cell therapies directed to the PRAME target which is expressed in a broad range of tumors. This program is being transitioned from GSK following termination of our collaboration agreement with GSK. Dependent on the data arising from the preclinical program, the first cell therapy targeting PRAME is anticipated to be IND-ready by the end of 2023.

​

1

Table of Contents

We are also developing allogeneic or “off-the-shelf” cell therapies utilizing a proprietary allogeneic platform. The platform utilizes cells derived from Induced Pluripotent Stem Cells (“iPSCs”), which can be gene-edited to express our engineered TCRs or other constructs and then differentiated into the required end cell type, for example T-cells. The platform is applicable to all of our cell therapies.

We have a strategic collaboration with Genentech Inc (“Genentech”). The collaboration with Genentech covers the research and development of “off-the-shelf” cell therapies for up to five shared cancer targets (“off-the-shelf” products) and the development of a novel allogeneic personalized cell therapy platform.

We also have several development and research collaborations including a clinical and preclinical alliance agreement with MD Anderson Cancer Center. A prior collaboration with GSK terminated during 2022 and we are negotiating a transition agreement with GSK in relation to ongoing clinical trials with T-cell therapies directed to the NY-ESO and PRAME targets. A prior Co-development and Co-commercialization agreement (the “Astellas Collaboration Agreement”) with Universal Cells, Inc., a wholly-owned subsidiary of Astellas Pharma Inc. (“Universal Cells”) under which we collaborated with Universal Cells to research, develop, and commercialize certain cellular therapy products directed to certain targets was mutually agreed to terminate as of March 6, 2023. Termination does not impact the development of our allogeneic cell lines for our internal allogeneic programs or for our collaboration with Genentech Inc. The parties previously terminated an Amended and Restated Research Collaboration and License Agreement, dated January 13, 2020, effective February 26, 2023.

​

We are an integrated cell therapy company with our own manufacturing facility in the U.S. for autologous products and in the United Kingdom (“U.K.”) for allogeneic products together with a dedicated lentiviral vector manufacturing suite in the UK within the Cell and Gene Therapy Catapult facility at Stevenage. This enables us to continue improving the patient experience associated with our cell therapies including the ability to rapidly introduce improvements to the manufacturing process and patient supply chain.

In November 2022 we took a decision to focus our clinical and preclinical programs on the MAGE-A4 and PRAME targets including the BLA submission for afami-cel. We have stopped the SURPASS-2 trial in GE cancers and the TIL-IL7 program. We have also paused any further investment in non-core activities including certain preclinical programs including the HiT program, additional target programs (other than the PRAME program) and alternative HLA programs. We also announced that investment in commercialization of afami-cel will be delayed given the BLA filing timelines. Given the de-prioritisation of non-core programs resulting from this decision, we are undertaking associated cost reduction activities including a reduction in headcount of approximately 25% which we currently estimate will extend our cash runway into early 2025. The headcount reduction has now concluded.

On March 6, 2023 we announced entry into a definitive agreement under which we will combine with TCR² Therapeutics Inc (“TCR²”) in an all-stock transaction to create a preeminent cell therapy company focused on treating solid tumors. The combination provides extensive advantages for clinical development and product delivery supported by complementary technology platforms. The lead clinical franchises for the combined company will utilize engineered T-cell therapies targeting MAGE-A4 and mesothelin. These targets are expressed on a broad range of solid tumors and are supported by early- and late-stage clinical data. The combined company also has a preclinical pipeline of additional target opportunities with development initially focused on PRAME and CD70. The merger agreement was unanimously approved by the boards of directors of both companies. Following the closing of the transaction, Adaptimmune shareholders will own approximately 75% of the combined company and TCR² stockholders will own approximately 25% of the combined company. The agreement contains customary representations, warranties and covenants given by us and TCR². The agreement also contains customary pre-closing covenants, including covenants by each of the parties relating to conduct of their respective business prior to the closing of the transaction. The transaction is expected to close in Q2 2023, subject to the receipt of approvals by Adaptimmune shareholders and TCR² stockholders and satisfaction or waiver of other customary closing conditions. Following the closing of the transaction we currently estimate that the cash runway of the combined company will extend into early 2026.

​

​

2

Table of Contents

Business Strategy

Building on our leadership position with engineered T-cell therapies in solid tumor indications, our strategic objective is to be a world leader in designing, developing and delivering cell therapies that transform the lives of people with cancer. Our objective is to revolutionize the treatment of solid tumors with a single dose of engineered TCR T-cells and as a result to address cancers with high unmet needs with both autologous and allogeneic solutions. To achieve our objectives, our primary core value drivers are as follows:

Filing the BLA for afami-cel and progressing towards commercialization of afami-cel. We initiated the rolling filing of the BLA with the FDA in Q4 2022 for use of afami-cel for the treatment of synovial sarcoma. Completion of the rolling filing of all modules of the BLA is targeted for mid-2023. Commercial preparations are underway for the launch of afami-cel in synovial sarcoma where there are limited options and a poor prognosis for individuals with advanced disease.

Progressing the ADP-A2M4CD8 T-cell therapy into later phase clinical trials. Subject to the data from the ongoing SURPASS family of clinical trials, we plan to rapidly progress clinical candidates through clinical trials and towards BLA filing. For example, our Phase 2 ovarian cancer trial with ADP-A2M4CD8 is initiating in 2023 and the SURPASS Phase 1 trial continues in multiple indications including with cohorts aimed at using ADP-A2M4CD8 in earlier lines of treatment alongside existing standard of care.

​

Progressing the ADP-A2M4CD8 T-cell therapy into earlier lines of therapy. We are initiating two new cohorts in the SURPASS trial in urothelial and head and neck cancers for patients with fewer lines of therapy and in combination with standard of care in those settings.

Progressing PRAME directed T-cell therapies into the clinic. We aim to complete preclinical development of our first T-cell therapy directed to PRAME during 2023 and file an IND rapidly following completion of preclinical studies.

Continuing to develop “off-the-shelf” cell immunotherapies and progress allogeneic cell therapies to the clinic. We continue to develop our “off-the-shelf” (allogeneic) platform, which is broadly applicable to cell therapies, both internally and in collaboration with our partners Astellas and Genentech.

Continuing to improve our manufacturing and patient supply processes to optimize how we deliver our cell therapies to patients. Our integrated cell therapy capabilities enable us to continually enhance our cell and vector manufacturing and supply processes which we believe will ultimately enable us to treat patients quicker, at a lower cost and more effectively. We have manufacturing facilities in the U.K. and U.S. and our U.S. manufacturing facility has been expanded in anticipation, pending FDA approval, of commercialization of afami-cel for the treatment of synovial sarcoma.

Our Cell Therapies for Cancer

The Immune System and T-cells

The immune system plays an important role in targeting and destroying cancer cells. Specifically, T-cells, which are a type of white blood cell, and their receptors create a natural system that is designed to scan the body for diseased cells. In general, cells process proteins internally and then convert these proteins into peptide fragments which are then presented on the cell surface by a protein complex called the Human Leukocyte Antigen (“HLA”). T-cells naturally scan all other cells in the body for the presence of abnormal peptide fragments, such as those generated from infectious agents. Recognition of this peptide-HLA complex takes place through the T-cell receptor or TCR expressed on the T-cells. However, binding of naturally occurring TCRs to cancer targets tends to be very poor because cancer proteins appear very similar to naturally occurring proteins on healthy cells.

3

Table of Contents

Cancer Target Identification and Validation

Before developing any engineered T-cell therapy, it is important to identify and validate a suitable target cancer peptide or protein. The target must be expressed only on the cancer cells of interest and with expression in normal non-cancerous tissue only where a risk to the patient would be deemed acceptable. Careful validation and identification of targets is important to ensure that any engineered cell therapy is specific to the targeted cancer and does not bind to the same target on non-cancer cells, or that the receptor in the cell therapy does not recognize a similar peptide or protein derived in normal cells.

​

Cell Therapies

We have developed a range of cell therapies all of which utilize the interaction between a T-cell via its TCRs and a peptide or protein. Our cell therapies can be made directly from a patient’s own T-cells (“autologous” cell therapies) or manufactured from stem cells (“allogeneic” cell therapies).

For all of our autologous cell therapies patient T-cells are extracted and are then engineered to generate the end cell therapy whether this is through engineering of the TCR itself or through the addition of another agent which enhances the efficacy of the TCR or T-cell. The nature of the engineering impacts the type of cell therapy product generated. The engineered T-cells are then expanded and infused back into the patient. When these T-cells encounter a recognized peptide or protein within the patient’s body, they multiply and initiate the destruction of the targeted cancer cells.

For our allogeneic T-cell therapies, Induced Pluripotent Stem Cells ("iPSCs”) are gene edited to express the engineered TCR or HiT and potentially a range of next gen modifications. As part of the gene editing the iPSCs are also edited to remove certain HLA-type expression so that patients expressing any HLA-type can be treated with the same end product. Those gene-edited iPSCs are then differentiated, using a number of directed process steps, into T-cells, which can then be used to treat patients expressing the tumor antigen to which the TCR or HiT is directed.

​

Our TCR T-cells (SPEAR T-cells)

Following identification of a suitable target peptide, we identify TCRs that are capable of binding to that target peptide or protein. We then engineer and optimize those identified receptors to enhance their ability to recognize and bind to the cancer targets, thereby enabling a highly targeted immunotherapy which complements a patient’s immune system. The optimized TCR or SPEAR-T-cell for the cell therapy then undergoes extensive preclinical safety testing prior to administration to patients. A lentiviral vector is used to transfer the engineered TCR into the patient’s T-cells if that patient has the relevant target and HLA type for our TCR cell therapy. The optimized cell therapy then undergoes extensive preclinical safety testing prior to administration to patients.

Our HiT Cell Therapies

Naturally occurring TCRs recognize peptides that are presented on the cell surface by a protein complex called HLA. Patient treatment with our SPEAR T-cells requires patients to express a particular HLA-type. We have now developed a TCR platform capable of producing TCRs able to recognize targets expressed on the surface of cancer cells independently of HLA-type. The TCR is engineered to recognize and bind to a cell surface protein. The HiT platform enables us to identify suitable targets and to then generate engineered HiTs which can bind and interact with those targets. These HLA-independent TCRs or HiTs use the same internal cell signaling processes as naturally occurring TCRs.

4

Table of Contents

Our Product Pipeline

MAGE-A4 franchise

​

We have multiple autologous cell therapies in clinical trials or entering clinical trials which target indications in which the MAGE-A4 antigen is expressed.

​

​

Afami-cel is a TCR T-cell therapy (“SPEAR T-cell”) directed to a MAGE-A4 peptide presented on HLA. The diagram below illustrates the SPEAR T-cell interacting with the MAGE-A4 antigen on the tumor cell.

​

​

​

5

Table of Contents

​

​

A registration directed Phase 2 clinical trial is underway in synovial sarcoma in which the MAGE-A4 antigen is expressed. Enrollment in Cohort 1 is complete, and the cohort met its primary endpoint. Cohort 2 of the trial is ongoing although enrollment has now met its target and ongoing enrollment is paused. A BLA is in the process of being filed with the FDA, with the first modules filed in December 2022. Completion of the rolling filing of all modules of the BLA is targeted for mid-2023.

​

Clinical data was presented at the Connective Tissue Oncology Society (“CTOS”) in November 2022. An Overall Response Rate (ORR) per independent review of approximately 39% in synovial sarcoma was presented together with a median duration of response of just over 50 weeks. Afami-cel continues to have an acceptable benefit to risk profile. The charts below summarize the best overall responses by RECIST v1.1 as of August 29, 2022 for cohort 1 of the Spearhead-1 trial.

​

​

​

The graph represents data from Cohort 1. PR= partial response; SD=stable-disease; PD=progressive disease. Data represent percent changes from baseline in sum of diameters (sum of the long diameters for non-nodal lesions and short axis for nodal lesions) in target lesions through progression or prior to surgical resection.

​

​

Orphan Drug designation for afami-cel for the treatment of soft tissue sarcomas has been granted in the European Union (“EU”) and U.S. together with Regenerative Medicine Advanced Therapy (“RMAT”) designation in the U.S. for the treatment of synovial sarcoma and access to the Priority Medicines (“PRIME”) Regulatory Support initiative by the European Medicines Agency (“EMA”) for the treatment of synovial sarcoma.

​

​

Phase 1 Trial with ADP-A2M4CD8

​

Enrollment is ongoing in a Phase 1 trial (“SURPASS” trial) for a next generation SPEAR T-cell, ADP-A2M4CD8. This next generation SPEAR T-cell utilizes the same engineered T-cell receptor as afami-cel, but with the addition of a CD8α homodimer. The addition of the CD8α homodimer has been shown in

6

Table of Contents

vitro to increase cytokine release and SPEAR T-cell potency. As of November 23, 2022 responses (per RECIST 1.1) were seen in five solid tumor indications with a 37% response rate across the whole trial. The following chart shows the responses seen in the trial.

​

​

​

​

​

​

​

​

​

​

​

​

​

​

​

​

​

​

​

​

​

​

​

​

​

​

​

​

​

PR= partial response; SD=stable-disease; PD=progressive disease. Data represent percent changes from baseline in sum of diameters (sum of the long diameters for non-nodal lesions and short axis for nodal lesions) in target lesions through progression or prior to surgical resection.

​

We are focusing recruitment in the SURPASS trial on head and neck cancer and urothelial cancer. Taken together with ovarian cancer, a response rate of 75% was seen as of November 23, 2022 in patients with three or fewer lines of therapy (9 out of 12 patients in trial). As a result of these data, we are initiating new cohorts within the SURPASS trial for treatment of earlier line patients in urothelial and head and neck cancers alongside standard of care treatment. We also continue to enroll in a cohort looking at the combination of ADP-A2M4CD8 with a checkpoint inhibitor.

​

The charts below show the responses seen in ovarian, urothelial and head and neck indications. Data provided is as of November 23, 2022.

​

​

7

Table of Contents

Data cut-off: Nov. 23, 2022, one non-evaluable patient with ovarian cancer not shown;

* oral, pharyngeal, and laryngeal cancers;

CR=complete response: PR=partial response; SD=stable disease; PD=progressive disease;

SOC=standard-of-care; PFS=progression free survival

​

​

​

Phase 2 Trial with ADP-A2M4CD8 in ovarian cancer: A Phase 2 trial with ADP-A2M4CD8 in ovarian cancer is initiating in early 2023 in collaboration with The GOG Foundation Inc. The trial will evaluate the T-cell therapy in both monotherapy and in combination with nivolumab (a checkpoint inhibitor) in platinum resistant ovarian cancer. We recently received FDA RMAT designation for ADP-A2M4CD8 for the treatment of patients with platinum resistant ovarian cancer.

​

Other Clinical Programs

​

Two further clinical programs, the ADP-A2AFP Phase 1 trial and the SURPASS-2 Phase 2 trial, have closed to enrollment. We are also in discussions with GSK in relation to the transition of clinical trial programs for cell therapies targeting the NY-ESO antigen across multiple tumors.

​

Preclinical Candidate Pipeline

Our aim is to utilize the insights we obtain from our clinical trials and translational sciences work to improve the efficacy of our existing products and approaches; and to increase the scope of our cell therapies and ability to treat an increasing number of patients. We are currently focusing our preclinical pipeline on the development of T-cell therapies to target PRAME expressing tumors and on our allogeneic cell therapies.

Allogeneic iPSC Platform

We continue to develop our allogeneic platform which can be used to generate ‘off-the-shelf’ cell therapies that are universally applicable to all eligible patients by developing gene-edited iPSCs which are differentiated to T-cells by our in-house proprietary process. These “off-the-shelf” cells are being developed to overcome the current limitation of autologous therapies that need to be manufactured specifically for each patient. Additionally, our process starts with iPSCs instead of donor-derived T-cells, which potentially reduces product variability.

The enhanced T-cell technology being developed involves selective engineering for the removal of potentially immunogenic cell surface proteins (for example, HLA molecules) and the addition of our TCRs, without the use of

8

Table of Contents

nucleases, to develop these T-cell products. If successful, this will enable us to treat our patients with an “off-the-shelf” or on demand cell therapy product without the need to acquire a patient’s own cells.

We have two collaboration programs, one with Astellas in which an allogeneic product incorporating a HiT targeting mesothelin is being developed (and a further target has been nominated); and one with Genentech, in which “off-the-shelf” cell therapies for up to five shared cancer targets (“off the shelf” products) and a novel allogeneic personalized cell therapy platform are being developed.

Integrated Cell Therapy Company

We are committed to building an integrated cell therapy company with a broad range of capabilities that enable the research and development of cell therapies, the translational analyses of clinical responses, control of the manufacturing and supply chain and commercialization. The ability to take learnings from every stage of the process and feed these learnings back into further research and development enables decisions to be taken at the appropriate time and improvements and enhancements to processes and products to be made effectively and in a timely manner.

We have our own autologous cell therapy manufacturing facility at the Navy Yard in Philadelphia, Pennsylvania which is capable of supplying all of our autologous cell therapies currently in the clinic. The Navy Yard facility will also support the anticipated commercial launch in the US of afami-cel. A new manufacturing facility dedicated to allogeneic drug product manufacture opened in 2022 and is co-located with our research facility in Milton Park in the U.K. We also have our own dedicated vector manufacturing capability in the U.K., within the Catapult Cell and Gene Therapy Manufacturing Centre in Stevenage, which is now able to produce lentiviral vector for our clinical trials using a proprietary suspension process.

Control of our own end-to-end manufacturing processes (including vector, T-cell and analytical quality control testing) enables us to improve and further develop these processes for manufacture of our cell therapies. The ability to manufacture in-house provides security of supply at a lower cost than using a third-party provider. In addition, the ability to continually evaluate and optimize processes enables ongoing reduction in the times taken to treat our patients and the overall cost of goods applicable to manufacture and supply of our cell therapies.

Core Alliances and Collaborations

Genentech Strategic Collaboration and License Agreement

On September 3, 2021, Adaptimmune Limited, a wholly-owned subsidiary of Adaptimmune Therapeutics Plc, entered into a Strategic Collaboration and License Agreement with Genentech, Inc. and F. Hoffman-La Roche Ltd (the “Agreement”).

​

The collaboration has two components:

​

The parties will collaborate to perform a research program, initially during an eight-year period (which may be extended for up to two additional two-year terms at Genentech’s election upon payment of an extension fee for each two-year term), to develop the cell therapies, following which Genentech will determine whether to further develop and commercialize such therapies.

​

Under the terms of the Agreement, Adaptimmune received a $150 million upfront payment. Adaptimmune may also receive:

​

9

Table of Contents

​

In addition, Adaptimmune will receive tiered royalties on net sales in the mid-single to low-double digits.

​

Adaptimmune also has a right to opt-in to receive a profit share and to co-promote “off-the-shelf” T-cell therapies. If Adaptimmune elects to opt in, then Adaptimmune will be eligible to share 50 percent of profits and losses from U.S. sales on such products and to receive up to $800 million in ex-U.S. regulatory and sales-based milestone payments, as well as royalties on ex-U.S. net sales.

​

The parties can terminate the Agreement in the event of material breach or insolvency of the other party. Genentech is entitled to terminate the Agreement in its entirety, on a product-by-product basis or collaboration target by collaboration target basis on provision of 180 days notice.

​

Universal Cells Co-development Collaboration Agreement

On January 13, 2020, the Company entered into a Co-development and Co-commercialization agreement (the “Astellas Collaboration Agreement”) with Universal Cells, Inc., a wholly-owned subsidiary of Astellas Pharma Inc. (“Universal Cells”).

​

Under the Astellas Collaboration Agreement the parties agreed on up to three targets with the aim of co-developing T-cell therapies directed to those targets pursuant to an agreed research plan. The Company and Universal Cells mutually agreed to terminate the agreement as of March 6, 2023. In connection with the termination, all licenses and sublicenses granted to either party pursuant to the Collaboration Agreement ceased, and each party is required to return all confidential information of the other party within 30 days of the Effective Date. Each party also agreed to destroy all cell lines and other materials of the other party in its possession within 30 days of the Effective Date. There were no termination penalties in connection with the termination.

In addition to the Astellas Collaboration Agreement, the parties previously entered into an agreement relating to the use of Universal Cells gene editing and HLA-editing technology in the context of our development of allogeneic T-cell therapies. This Agreement was terminated by notice on January 27, 2023, effective 30 days following receipt of notice of termination. Termination follows our decision to change the cell line being used to develop its MAGE-A4 allogeneic cell therapy due to the presence of a chromosomal abnormality in the original cell line provided by Universal Cells under the Agreement. As a result of termination, all licenses between the parties to the Agreement will cease and each party is required to return all confidential information of the other party.

​

Development and Research Collaborations

GSK Collaboration and License Agreement

We entered into the GSK Collaboration and License Agreement regarding the development, manufacture and commercialization of TCR therapeutic candidates in May 2014. The collaboration was terminated in October 2022 and we are in discussions with GSK in relation to the transition of the NY-ESO and PRAME programs under the collaboration agreement to Adaptimmune. A further amendment to the collaboration agreement was entered into on December 19, 2022 for the deletion of certain provisions relating to GSK’s post termination manufacturing and supply obligations and payment of £5 million by GSK to Adaptimmune.

​

10

Table of Contents

Preclinical and Clinical Collaborations

We have third-party collaborations in place with Noile-Immune and Alpine Immune Sciences.

With Alpine, we are collaborating to develop next-generation SPEAR T-cell products that incorporate Alpine’s secreted and transmembrane immunomodulatory protein technology. The collaboration agreement was announced in May 2019, and we believe that the Alpine technology could complement our existing internal next generation technology and enhance anti-tumor potential through engagement of further rapid and flexible immunomodulatory mechanisms.

In the Noile-Immune collaboration, announced in August 2019, we will co-develop next-generation SPEAR T-cell products, incorporating Noile-Immune’s PRIME (proliferation inducing and migration enhancing) technology, based upon co-expression of IL-7 and CCL19.

We also have a strategic alliance agreement with the MD Anderson Cancer Center which covers both the conduct of certain clinical trials for our SPEAR T-cell therapies and also certain pre-clinical research work.

Intellectual Property

We seek to protect the intellectual property and proprietary technology that we believe is important to our business, including seeking, maintaining, enforcing and defending patent rights for our SPEAR T-cells and processes, whether developed internally or licensed from third parties. Our success will depend on our ability to obtain and maintain patent and other protection including data/market exclusivity for our cell therapies, manufacturing and platform technology, preserve the confidentiality of our know-how and trade secrets and operate without infringing the valid and enforceable patents and proprietary rights of third parties. See “Risk Factors—Risks Related to Our Intellectual Property.”

Our policy is to seek to protect our proprietary position generally by filing an initial priority filing at the U.K. Intellectual Property Office (“UKIPO”) and/or the U.S. Patent Trademark Office (“USPTO”). This is followed by the filing of a patent application under the Patent Co-operation Treaty (“PCT”) claiming priority from the initial application(s) and then application for patent grant in, for example, the U.S., Europe (including major European territories), Japan, Australia, New Zealand, India and Canada. In each case, we determine the strategy and territories required after discussion with our patent professionals to ensure that we obtain relevant coverage in territories that are commercially important to us and reflect the scope of cell therapies being developed. We will additionally rely on data exclusivity, market exclusivity and patent term extensions when available, including as relevant exclusivity through orphan or pediatric drug designation. We also rely on trade secrets and know-how relating to our underlying platform technologies, manufacturing processes and pre-clinical candidates.

Product Patent Families

Afami-cel  - We own three patent families covering the composition of matter of ADP-A2M4 and other related TCRs and T-cell therapies. The patent application claims are primarily directed to the engineered TCR therapeutic candidate and in particular the amino acid substitutions required for such engineered TCR therapeutic candidate. National/regional applications have been filed via the PCT in all commercially relevant territories and claims have been allowed in Europe and the US. We project the patents within these families, if issued, and if the appropriate maintenance, renewal, annuity, or other governmental fees are paid, will expire in 2037 (worldwide, excluding possible patent term extensions). PCT applications have also been filed in relation to the use of ADP-A2M4 TCR in the treatment of head and neck, lung and ovarian cancers.

ADP-A2M4CD8 – We own a patent family covering the composition of matter of ADP-A2M4CD8 and other related TCR T-cell therapies. The patent application claims are directed to the engineered TCR therapeutic candidate in combination with the CD8 next generation technology. We project the patents within this family, if issued, and if the appropriate maintenance, renewal, annuity, or other governmental fees are paid, to expire in 2039 (worldwide, excluding

11

Table of Contents

possible patent term extensions). PCT applications have also been filed in relation to the use of A2M4CD8 TCR in the treatment of esophageal and gastric cancers, head and neck, urothelial and ovarian cancers.

PRAME TCR T-cell – We have filed a priority patent application covering the composition of matter of the TCR T-cell therapy family directed to the PRAME target. The patent application claims are primarily directed to the engineered TCR candidate and in particular to the amino acid substitutions required for such TCR candidate. National and regional applications will be filed via the PCT in due course.

Platform Technology

We own a number of platform technology patents and patent applications which are directed to certain aspects of the process that we use to engineer our SPEAR TCRs and other cell therapies. Some of these are owned jointly with Immunocore Limited, with whom we have historically had a shared development history.

Manufacturing Process Patents and Patent Applications

We have trade secrets and patent applications relating to the manufacture of our cell therapies. For example, we have filed patent applications in commercially relevant territories, which claim priority from initial priority patent applications filed at the USPTO and UKIPO, which are directed to a particular modification to the lentiviral vector technology. We believe this modification enhances the safety profile of the lentiviral vector technology. This has been granted in the U.S. Further patent applications have been filed on the manufacturing and quality control of our products.

Preclinical and Next Generation Approaches

We have filed seven patent families covering a range of next generation technology approaches and/or combination approaches.

Allogeneic iPSC Platform Approaches

We have filed a number of patent applications covering our proprietary iPSC stem cell differentiation technology which enables the differentiation of stem cells into T-cells which can then be administered to patients. The patent applications are primarily directed to the various stages required for the differentiation of the iPSC stem cells into different cell line types including NK cells, NKT cells, macrophages, dendritic cells and T-cells. The earliest of these applications have now been filed as PCT applications and will be pursued in all commercially relevant territories. Patent protection is projected to extend to 2040 (worldwide, excluding possible patent term extensions).

Third-Party Intellectual Property Rights

We have a non-exclusive license from ThermoFisher Inc. under certain of its intellectual property rights covering its Dynabeads® CD3/CD28 technology. This technology is used in our manufacturing process to isolate, activate and expand patient T-cells. We also have a supply agreement which runs until December 31, 2025. See “Risk Factors—Risks Related to Our Reliance Upon Third Parties—We rely heavily on ThermoFisher and the technology we license from them.”

Whether licenses are required under any third-party patents depends on what steps we take going forward in relation to our manufacturing processes, development processes and development products including our allogeneic manufacturing and differentiation process. We may need to negotiate a license under any third-party patents or develop alternative strategies for dealing with any third party patents if licenses are not available on commercially acceptable terms or at all.

Competition

The biotechnology and pharmaceutical industries are characterized by rapidly advancing technologies and intense competition. Competitors include large pharmaceutical companies with established development and

12

Table of Contents

commercialization programs, biotechnology companies with varying development and commercialization capabilities and academic centers developing novel technologies and products.

​

We face competition in all of the following areas:

​

​

​

​

​

​

Where we see competition in any indication and a competitor receives marketing approval before our cell therapy, we will need to demonstrate increased efficacy over the competing product.

​

Government Regulation and Product Approvals

Government authorities in the U.S., at the federal, state and local level, and in other countries and jurisdictions, including the EU and U.K, extensively regulate, among other things, the research, development, testing, manufacture, quality control, approval, packaging, storage, recordkeeping, labeling, advertising, promotion, distribution, marketing, post-approval monitoring and reporting, and import and export of pharmaceutical products. The processes for obtaining regulatory approvals in the U.S. and in foreign countries and jurisdictions, along with subsequent compliance with applicable statutes and regulations and other regulatory authorities, require the expenditure of substantial time and financial resources. Failure to comply with the various federal, state and local level laws and requirements can also result in severe penalties and restrictions to the business.

13

Table of Contents

FDA Approval Process

In the U.S., therapeutic products, including drugs, biologics, and medical devices are subject to extensive regulation by the FDA. The Federal Food, Drug, and Cosmetic Act (the “FDC Act”), and other federal and state statutes and regulations, govern, among other things, the research, development, testing, manufacture, storage, recordkeeping, approval, labeling, promotion and marketing, distribution, post-approval monitoring and reporting, sampling, and import and export of pharmaceutical products, including biological products. Biological products are subject to regulation under the FDC Act, and are approved for marketing under provisions of the Public Health Service Act (“PHSA”) via a BLA. The application process and requirements for approval of BLAs are generally similar to those for new drug applications (“NDAs”), and biologics are associated with generally similar, if not greater, approval risks and costs as drugs. Failure to comply with applicable U.S. requirements may subject a company to a variety of administrative or judicial sanctions, such as FDA refusal to approve pending NDAs or BLAs, clinical holds, warning or untitled letters, product recalls, product seizures, total or partial suspension of production or distribution, injunctions, fines, civil penalties, and criminal prosecution.

Biological product development for a new product or certain changes to an approved product in the U.S. typically involves:

​

Satisfaction of FDA pre-market approval requirements typically takes many years and the actual time required may vary substantially based upon the type, complexity, and novelty of the product or disease.

Preclinical Studies

Preclinical studies include laboratory evaluation of product biochemistry, formulation and stability, as well as in vitro and animal studies to assess the potential for toxicity and to establish a rationale for therapeutic use for supporting subsequent clinical testing. In the United States, certain preclinical trials must comply with the FDA's Good Laboratory Practice requirements ("GLPs") and the U.S. Department of Agriculture's Animal Welfare Act, as well as other federal regulations and requirements.

IND Submission

In order to begin clinical testing of an investigational biologic product, the results of the preclinical tests, together with manufacturing information, analytical data, any available clinical data or literature and a proposed clinical protocol, among other things, are submitted to the FDA as part of an IND. An IND is a request for authorization from the FDA to administer an investigational product to humans and must become effective before human clinical trials may begin. Some long-term preclinical testing, such as animal tests of reproductive adverse events and carcinogenicity, may continue after the IND is submitted. An IND automatically becomes effective 30 days after receipt by the FDA, unless before that time the FDA raises concerns or questions related to one or more proposed clinical trials and places the trial on clinical hold. In such a case, the IND sponsor and the FDA must resolve any outstanding concerns before the clinical trial can begin. As a result, submission of an IND may not result in the FDA allowing clinical trials to commence.

Clinical Studies

The clinical stage of development involves the administration of the investigational product to healthy volunteers or patients under the supervision of qualified investigators, generally physicians not employed by or under the trial sponsor’s control, in accordance with Good Clinical Practice (“GCP”) requirements, which include the requirement that all research subjects provide their informed consent for their participation in any clinical trial. Clinical trials are conducted under protocols detailing, among other things, the objectives of the clinical trial, dosing procedures, subject

14

Table of Contents

selection and exclusion criteria and the parameters to be used to monitor subject safety and assess efficacy. Each protocol, and any subsequent amendments to the protocol, must be submitted to the FDA as part of the IND. Furthermore, each clinical trial must be reviewed and approved by an Investigational Review Board (“IRB”) for each institution at which the clinical trial will be conducted to ensure that the risks to individuals participating in the clinical trials are minimized and are reasonable in relation to anticipated benefits. The IRB also approves the informed consent form that must be provided to each clinical trial subject or his or her legal representative and must monitor the clinical trial until completed. There also are requirements governing the reporting of ongoing clinical trials and completed clinical trial results to public registries.

Clinical trials to support BLAs for marketing approval are typically conducted in three sequential phases, but the phases may overlap. In Phase 1, the initial introduction of the biologic into healthy human subjects or patients, the product is tested to assess metabolism, pharmacokinetics, pharmacological actions, side effects associated with increasing doses, and, if possible, early evidence on effectiveness. Phase 2 usually involves trials in a limited patient population to determine the effectiveness of the drug or biologic for a particular indication, dosage tolerance, and optimum dosage, and to identify common adverse effects and safety risks. If a compound demonstrates evidence of effectiveness and an acceptable safety profile in Phase 2 evaluations, Phase 3 trials are undertaken to obtain the additional information about clinical efficacy and safety in a larger number of patients, typically at geographically dispersed clinical trial sites, to permit the FDA to evaluate the overall benefit-risk relationship of the drug or biologic and to provide adequate information for the labeling of the product.

The FDA may order the temporary, or permanent, discontinuation of a clinical trial at any time, or impose other sanctions, if it believes that the clinical trial either is not being conducted in accordance with FDA requirements or presents an unacceptable risk to the clinical trial patients. An Investigational Review Board (“IRB”) may also require the clinical trial at the site to be halted, either temporarily or permanently, for failure to comply with the IRB’s requirements, or may impose other conditions.

In December 2022, Congress passed the Food and Drug Omnibus Reform Act (“FDORA”), which includes provisions related to diversity in clinical trial enrollment. Once the new provisions go into effect, sponsors conducting a phase three study or another pivotal study must submit a diversity action plan to the FDA by the time they submit their study protocol. The FDA may waive the requirement to submit a diversity action plan if a waiver is necessary due to the prevalence or incidence of the disease or condition that is the subject of the trial or the patient population that may use the drug or device, or if implementing a diversity action plan would be impracticable, or against the public health interest during a public health emergency. The FDA may apply a waiver on its own initiative or at the request of a sponsor. If a sponsor requests a waiver, the FDA must grant or deny a waiver within 60 days of receiving such a request.

BLA Review Process

After completion of the required clinical testing, a BLA is prepared and submitted to the FDA. FDA approval of the BLA is required before marketing of the product may begin in the U.S. The BLA must include the results of all preclinical, clinical, and other testing, compilation of data relating to the product’s pharmacology, chemistry, manufacture, and controls, as well as proposed labeling for the product.

Under the Prescription Drug User Fee Act (“PDFUA”), the FDA has 60 days from its receipt of a BLA to determine whether the application will be accepted for filing based on the agency’s threshold determination that it is sufficiently complete to permit substantive review. Once the submission is accepted for filing, the FDA begins an in-depth review. Under PDUFA, the FDA has agreed to certain performance goals in the review of BLAs. Under Standard Review, applications for new biologic products are reviewed within 10 months of the date the FDA filed the BLA (approximately 60 days after receipt); under Priority Review, BLAs are reviewed within six months of the date the FDA filed the BLA. Priority Review can be applied to a biologic that the FDA determines has the potential to treat a serious or life-threatening condition and, if approved, would be a significant improvement in safety or effectiveness compared to available therapies. The FDA does not always meet its PDUFA goal dates for Standard and Priority BLAs, and the review process can be extended by FDA requests for additional information or clarification.

15

Table of Contents

Before approving a BLA, the FDA will conduct a pre-approval inspection of the manufacturing facilities for the new product to determine whether they comply with Good Manufacturing Practices (“cGMP”) requirements. The FDA will not approve the product unless it determines that the manufacturing processes and facilities are in compliance with cGMP requirements and adequate to assure consistent production of the product within required specifications. The FDA also may audit data from clinical trials to ensure compliance with GCP requirements. Additionally, the FDA may refer applications for novel drug products or drug products which present difficult questions of safety or efficacy to an advisory committee, typically a panel that includes physicians and other experts, for review, evaluation and a recommendation as to whether the application should be approved and under what conditions, if any. The FDA is not bound by recommendations of an advisory committee, but it considers such recommendations when making decisions on approval.

After the FDA evaluates the BLA, it issues either an approval letter or a Complete Response Letter (“CRL”). An approval letter authorizes commercial marketing of the drug with specific prescribing information for specific indications. A Complete Response Letter indicates that the review cycle of the application is complete and the application will not be approved in its present form. A CRL generally outlines the deficiencies in the submission and may identify substantial additional testing, or information, that must be developed in order for the FDA to reconsider the application. If, or when, those deficiencies have been addressed to the FDA’s satisfaction in a resubmission of the BLA, the FDA will issue an approval letter. The FDA has committed to reviewing such resubmissions in two or six months depending on the type of information included.

As a condition of BLA approval, the FDA may require a Risk Evaluation And Mitigation Strategy (“REMS”) to help ensure that the benefits of the biologic outweigh the potential risks. REMS can include medication guides, communication plans for healthcare professionals, and elements to assure safe use (“ETASU”). ETASU can include, but are not limited to, special training or certification for prescribing or dispensing, dispensing only under certain circumstances, special monitoring, and the use of patient registries.

Expedited Development Programs

The FDA is required to facilitate the development, and expedite the review, of certain biologics that are intended for the treatment of a serious or life-threatening disease or condition for which there is no effective treatment, which demonstrate the potential to address unmet medical needs for the condition, and/or would provide an improvement over existing therapies. These expedited programs include Fast Track designation, Breakthrough Therapy designation, Accelerated Approval, and Priority Review:

16

Table of Contents

​

Fast Track designation, Breakthrough Therapy designation, Priority Review, and Accelerated Approval generally do not change the standards for approval, but may expedite the development or approval process.

Regenerative Medicine Advanced Therapy designation

As part of the 21st Century Cures Act, Congress created the Regenerative Medicine Advanced Therapy (“RMAT”) designation to facilitate an efficient development program for, and expedite review of, a product candidate that meets the following criteria:

​

A sponsor may request that the FDA designate a drug as a RMAT concurrently with or at any time after submission of an IND. The FDA has 60 calendar days to determine whether the drug meets the criteria. A BLA for a regenerative medicine therapy that has received RMAT designation may be eligible for Priority Review or Accelerated Approval through use of surrogate or intermediate endpoints reasonably likely to predict long-term clinical benefit, or reliance upon data obtained from a meaningful number of sites. Benefits of RMAT designation also include early interactions with FDA to discuss any potential surrogate or intermediate endpoint to be used to support accelerated approval. A regenerative medicine therapy with RMAT designation that is granted Accelerated Approval and is subject to post-approval requirements may, as appropriate, fulfill such requirements through the submission of clinical evidence from clinical trials, patient registries, or other sources of real world evidence, such as electronic health records; the collection of larger confirmatory data sets; or post-approval monitoring of all patients treated with such therapy prior to its approval. Like some of FDA’s other expedited development programs, RMAT designation does not change the standards for approval but may help expedite the development or approval process.

Orphan Drug Designation

Under the Orphan Drug Act, the FDA may grant orphan drug designation to drug or biological products intended to treat a rare disease or condition. A rare disease or condition is one that affects fewer than 200,000 individuals in the U.S., or if it affects more than 200,000 individuals in the U.S., for which there is no reasonable expectation that the cost of developing and making a product available in the U.S. for such disease or condition will be recovered from sales of the product. Orphan drug designation must be requested before submitting a BLA. After the FDA grants orphan drug designation, the identity of the biological product and its potential orphan use are disclosed publicly by the FDA. Orphan drug designation does not convey any advantage in, or shorten the duration of, the regulatory review and approval process.

17

Table of Contents

Orphan drug designation confers several benefits, including certain tax credits for clinical research, a waiver of the BLA application fee, and exemption from certain pediatric study requirements, among others. The key benefit of orphan drug designation is orphan drug exclusivity, which is a seven-year exclusive marketing period in the U.S. for that product for that indication. Generally, the first BLA applicant with FDA orphan drug designation for a particular biological substance to treat a particular disease that obtains FDA approval is entitled to orphan drug exclusivity. During the orphan drug exclusivity period, the FDA may not approve any other applications to market the same biological product for the same rare disease or condition, with limited exceptions. One exception is if the later application can demonstrate clinical superiority to the biological product with orphan drug exclusivity. Clinical superiority may be shown by greater efficacy, greater safety, or a major contribution to patient care.

Orphan drug exclusivity does not prevent the FDA from approving a different drug or biological product for the same disease or condition, or the same biological product for a different disease or condition.

Pediatric Data and Study Requirements

Under the Pediatric Research Equity Act (“PREA”), NDAs or BLAs (as well as efficacy supplements) must contain data to assess the safety and effectiveness of the drug or biological product for the claimed indications in all relevant pediatric subpopulations and to support dosing and administration for each pediatric subpopulation for which the drug or biological product is approved as safe and effective. The FDA may, on its own initiative or at the request of the applicant, grant full or partial waivers, or deferrals, for submission of these assessments. With enactment of the Food and Drug Administration Safety and Innovation Act (“FDASIA”) in 2012, sponsors must also submit pediatric study plans (“PSPs”) within sixty days of an end-of-phase 2 meeting, or as may be agreed between the sponsor and FDA. Those plans must contain an outline of the proposed pediatric study or studies the applicant plans to conduct, including study objectives and design, any deferral or waiver requests, and other information required by regulation. The applicant, the FDA, and the FDA’s internal review committee must then review the information submitted, consult with each other, and agree upon a final plan. The FDA or the applicant may request an amendment to the plan at any time.Unless otherwise required by regulation, PREA does not apply to any biological product for an indication for which orphan designation has been granted.

Under the Best Pharmaceuticals for Children Act (“BPCA”), a sponsor may qualify for “pediatric exclusivity” if it conducts pediatric studies in response to a Written Request issued by FDA. Pediatric exclusivity extends by 6 months the period of other regulatory exclusivities, such as orphan drug exclusivity, so long as those exclusivity periods will not expire within 9 months of the award of pediatric exclusivity. For drug products, pediatric exclusivity will also extend the preclusive effect of patents on the FDA’s authority to approve certain competitor applications. Pediatric exclusivity does not extend patents for biological products approved under BLAs. To qualify for pediatric exclusivity, a sponsor must conduct studies that fairly respond to a Written Request, which outlines in detail the nature and type of studies that must be conducted. The studies need not show the product to be effective in the pediatric population; so long as the clinical studies are determined to fairly respond to the Written Request, pediatric exclusivity will be awarded. The FDA may issue a Written Request on its own initiative or at the sponsor’s request. A Written Request can include multiple studies in both approved and “off-label” indications.

Additional Controls for Biologics

To help reduce the increased risk of the introduction of adventitious agents, the PHSA emphasizes the importance of manufacturing controls for products whose attributes cannot be precisely defined. The PHSA also provides authority to the FDA to immediately suspend licenses in situations where there exists a danger to public health, to prepare or procure products in the event of shortages and critical public health needs, and to authorize the creation and enforcement of regulations to prevent the introduction or spread of communicable diseases in the U.S. and between states.

After a BLA is approved, the product may also be subject to official lot release as a condition of approval. As part of the manufacturing process, the manufacturer is required to perform certain tests on each lot of the product before it is released for distribution. If the product is subject to official release by the FDA, the manufacturer submits samples of each lot of product to the FDA together with a release protocol showing a summary of the history of manufacture of

18

Table of Contents

the lot and the results of all of the manufacturer’s tests performed on the lot. The FDA may also perform certain confirmatory tests on lots of some products, such as viral vaccines, before releasing the lots for distribution by the manufacturer. In addition, the FDA conducts laboratory research related to the regulatory standards on the safety, purity, potency, and effectiveness of biological products. As with drugs, after approval of biologics, manufacturers must address any safety issues that arise, are subject to recalls or a halt in manufacturing, and are subject to periodic inspection after approval.

Biosimilars

The Biologics Price Competition and Innovation Act of 2009 (“BPCIA”) created an abbreviated approval pathway for biological products shown to be “highly similar” to or “interchangeable” with an FDA-licensed reference biological product. Under the BPCIA, an application for a biosimilar product must contain evidence to show that the biosimilar product is “highly similar” to an approved reference biological product, notwithstanding minor differences in clinically inactive components and that there are no clinically meaningful differences between the biological product and the reference product in terms of safety, purity, and potency. Data to show biosimilarity can include: (1) analytical studies; (2) animal studies; and (3) a clinical study or studies. The FDA has the discretion not to require each of these categories of data. A biosimilar can be approved by the FDA for some or all of the same conditions of use, strengths, dosage forms, and routes of administration as the FDA-approved reference product. Interchangeability requires that a product is biosimilar to the reference product and the product must demonstrate that it can be expected to produce the same clinical results as the reference product in any given patient and, for products that are administered multiple times to an individual, the biologic and the reference biologic may be alternated or switched after one has been previously administered without increasing safety risks or risks of diminished efficacy relative to exclusive use of the reference biologic. At this time, it is unclear whether products deemed “interchangeable” by the FDA will, in fact, be readily substituted by pharmacies, which are governed by state pharmacy law.

Under the BPCIA, an application for a biosimilar product may not be submitted to the FDA until four years following the date that the reference product was first licensed by the FDA. In addition, the approval of a biosimilar product may not be made effective by the FDA until 12 years from the date on which the reference product was first licensed. During this 12-year period of exclusivity, another company may still market a competing version of the reference product if the FDA approves a full BLA for the competing product containing that applicant’s own preclinical data and data from adequate and well-controlled clinical trials to demonstrate the safety, purity and potency of the product.

The BPCIA also created certain exclusivity periods for biosimilars approved as interchangeable products. The first biologic product submitted under the abbreviated approval pathway that is determined to be interchangeable with the reference product has exclusivity against a finding of interchangeability for other biologics for the same condition of use for the lesser of (i) one year after first commercial marketing of the first interchangeable biosimilar, (ii) 18 months after the first interchangeable biosimilar is approved if there is no patent challenge, (iii) 18 months after resolution of a lawsuit over the patents of the reference biologic in favor of the first interchangeable biosimilar applicant, or (iv) 42 months after the first interchangeable biosimilar has been approved if a patent lawsuit is ongoing within the 42-month period.

The BPCIA is complex and continues to be interpreted and implemented by the FDA. In addition, government proposals have sought to reduce the 12-year reference product exclusivity period. Other aspects of the BPCIA, some of which may impact the BPCIA exclusivity provisions, have also been the subject of recent litigation. As a result, the ultimate impact, implementation, and impact of the BPCIA is subject to significant uncertainty.

Post-Approval Requirements

Approved drug and biological products are subject to ongoing regulation by the FDA, including, among other things, requirements relating to quality control and quality assurance, record-keeping, reporting of adverse experiences, periodic reporting, product sampling and distribution, and advertising and promotion of the product. After approval, most changes to the approved product, such as adding new indications or other labeling claims, are subject to prior FDA review and approval. There also are continuing user fee requirements, under which FDA assesses an annual program fee

19

Table of Contents

for each product identified in an approved BLA. Biologic manufacturers and their subcontractors are required to register their establishments with the FDA and certain state agencies, and are subject to periodic unannounced inspections by the FDA and certain state agencies for compliance with cGMP, which impose certain procedural and documentation requirements upon us and our third-party manufacturers. Changes to the manufacturing process are strictly regulated, and, depending on the significance of the change, may require prior FDA approval before being implemented. FDA regulations also require investigation and correction of any deviations from cGMP and impose reporting requirements upon us and any third-party manufacturers that we may decide to use. Accordingly, manufacturers must continue to expend time, money and effort in the area of production and quality control to maintain compliance with cGMP and other aspects of regulatory compliance.

The FDA may withdraw approval if compliance with regulatory requirements and standards is not maintained or if problems occur after the product reaches the market. Later discovery of previously unknown problems with a product, including AEs of unanticipated severity or frequency, or with manufacturing processes, or failure to comply with regulatory requirements, may result in revisions to the approved labeling to add new safety information; imposition of post-market studies or clinical studies to assess new safety risks; or imposition of distribution restrictions or other restrictions under a REMS program. Other potential consequences include, among other things:

​

The FDA closely regulates the marketing, labeling, advertising and promotion of biologics. A sponsor may only make claims relating to safety and efficacy, purity and potency that are approved by the FDA and in accordance with the provisions of the approved label. The FDA and other agencies actively enforce the laws and regulations prohibiting the promotion of off-label uses. Failure to comply with these requirements can result in, among other things, adverse publicity, warning letters, corrective advertising and potential civil and criminal penalties. Physicians may prescribe legally available products for uses that are not described in the product’s labeling and that differ from those tested by us and approved by the FDA. The FDA does not regulate the behavior of physicians in their choice of treatments. The FDA does, however, restrict manufacturer’s communications on the subject of off-label use of their products.

FDA Regulation of Companion Diagnostics

If safe and effective use of a therapeutic product depends on an in vitro diagnostic, the FDA generally will require approval or clearance of the diagnostic, known as a companion diagnostic, at the same time that the FDA approves the therapeutic product. The FDA has generally required in vitro companion diagnostics intended to select the patients who will respond to cancer treatment to obtain marketing approval through the pre-market approval (“PMA”) process for that diagnostic simultaneously with approval of the therapeutic. The review of these in vitro companion diagnostics in conjunction with the review of a cancer therapeutic involves coordination of review by the FDA’s Center for Biologics Evaluation and Research (“CBER”) and by the FDA’s Center for Devices and Radiological Health (“CDRH”).

The PMA process involves a rigorous premarket review during which the applicant must prepare and provide the FDA with reasonable assurance of the device’s safety and effectiveness and information about the device and its components regarding, among other things, device design, manufacturing and labeling. In addition, PMAs for certain devices must generally include the results from extensive preclinical and adequate and well-controlled clinical trials to establish the safety and effectiveness of the device for each indication for which FDA approval is sought.

20

Table of Contents

Successful PMA approval is uncertain, and the FDA may ultimately respond to a PMA submission with a not approvable determination based on deficiencies in the application and require additional clinical trial or other data that may be expensive and time-consuming to generate and that can substantially delay approval. If the FDA finds the PMA application is approvable, the FDA typically issues an approvable letter requiring the applicant’s agreement to specific conditions, such as changes in labeling, or specific additional information, such as submission of final labeling, in order to secure final approval of the PMA. If the FDA concludes that the applicable criteria have been met, the FDA will issue a PMA for the approved indications, which can be more limited than those originally sought by the applicant. The PMA can include post-approval conditions that the FDA believes necessary to ensure the safety and effectiveness of the device, including, among other things, restrictions on labeling, promotion, sale and distribution.

Anti-Kickback, False Claims Laws

In addition to FDA restrictions on marketing of pharmaceutical products, several other types of state and federal laws have been applied to restrict certain marketing practices in the pharmaceutical industry in recent years. These laws include anti-kickback statutes, false claims statutes, and other statutes pertaining to health care fraud and abuse. The federal healthcare program anti-kickback statute prohibits, among other things, knowingly and willfully offering, paying, soliciting or receiving remuneration to induce, or in return for, purchasing, leasing, ordering or arranging for the purchase, lease or order of any healthcare item or service reimbursable under Medicare, Medicaid, or other federally financed healthcare programs. Violations of the anti-kickback statute are punishable by imprisonment, criminal fines, civil monetary penalties, and exclusion from participation in federal healthcare programs.

Federal false claims laws prohibit any person from knowingly presenting, or causing to be presented, a false claim for payment to the federal government, or knowingly making, or causing to be made, a false statement to have a false claim paid. In addition, certain marketing practices, including off-label promotion, may also violate false claims laws. Additionally, the Healthcare Reform Act amended the federal false claims law such that a violation of the federal healthcare program anti-kickback statute can serve as a basis for liability under the federal false claims law.

Other federal statutes pertaining to healthcare fraud and abuse include the civil monetary penalties statute, which prohibits the offer or payment of remuneration to a Medicaid or Medicare beneficiary that the offeror/payor knows or should know is likely to influence the beneficiary to order a receive a reimbursable item or service from a particular supplier, and the healthcare fraud statute, which prohibits knowingly and willfully executing or attempting to execute a scheme to defraud any healthcare benefit program or obtain by means of false or fraudulent pretenses, representations, or promises any money or property owned by or under the control of any healthcare benefit program in connection with the delivery of or payment for healthcare benefits, items, or services.

Other Federal and State Regulatory Requirements

Various federal, state and local laws, regulations, and recommendations relating to safe working conditions, laboratory practices, the experimental use of animals, the environment and the purchase, storage, movement, import, export, use, and disposal of hazardous or potentially hazardous substances, including radioactive compounds and infectious disease agents, used in connection with our research are applicable to our activities. They include, among others, the U.S. Atomic Energy Act, the Clean Air Act, the Clean Water Act, the Occupational Safety and Health Act, the National Environmental Policy Act, the Toxic Substances Control Act, and Resources Conservation and Recovery Act, national restrictions on technology transfer, import, export, and customs regulations, and other present and possible future local, state, or federal regulation.

​

European Union, UK and Rest of the World Regulation

In addition to regulations in the U.S., we are subject to a variety of regulations in other jurisdictions both due to the location of our facilities and the fact that we are engaging in clinical programs outside of the U.S. and will need to obtain worldwide regulatory approval for our TCR therapeutic candidates. In particular we have clinical trials ongoing in the United Kingdom and in certain countries in the European Union (“EU”) and are subject to regulations relating to performance of those clinical trials and manufacture and supply of our cell therapies in those countries. Prior to supplying any cell therapy in any country or starting any clinical trials in any country outside of the U.S. we must obtain

21

Table of Contents

the requisite approvals from regulatory authorities in such countries. The existence of a U.S. regulatory approval does not guarantee that regulatory approvals will be obtained in other countries in which we wish to conduct clinical trials or market our cell therapies. In the EU, for example, a clinical trial application must be submitted to each country’s national health authority and an independent ethics committee, much like the FDA and IRB, respectively prior to any clinical trial being conducted in the relevant country. A marketing authorization application is then submitted to the EMA for approval by the European Commission. Finally, prior to any commercial supply, a pricing and reimbursement application is submitted to each relevant country’s national or local health authority(ies).

The requirements and process governing the conduct of clinical trials, product licensing, pricing and reimbursement vary from country to country. In all cases, the clinical trials are conducted in accordance with Good Clinical Practice (“GCP”) and the applicable regulatory requirements and the ethical principles that have their origin in the Declaration of Helsinki. However, the interpretation of these requirements may well differ from country to country.

Review and Approval of Drug Products Outside of the U.S.

In order to market any product outside of the U.S., a company must also comply with numerous and varying regulatory requirements of other countries and jurisdictions regarding quality, safety and efficacy and governing, among other things, clinical trials, marketing authorization, commercial sales and distribution of products. Whether or not it obtains FDA approval for a product, the company would need to obtain the necessary approvals by the comparable foreign regulatory authorities before it can commence clinical trials or marketing of the product in those countries or jurisdictions. The approval process ultimately varies between countries and jurisdictions and can involve additional product testing and additional administrative review periods. The time required to obtain approval in other countries and jurisdictions might differ from and be longer than that required to obtain FDA approval. Regulatory approval in one country or jurisdiction does not ensure regulatory approval in another, but a failure or delay in obtaining regulatory approval in one country or jurisdiction may negatively impact the regulatory process in others.

Procedures Governing Approval of Products in the EU and U.K.

Pursuant to the European Clinical Trials Directive, a system for the approval of clinical trials in the EU has been implemented through national legislation of the member states. Under this system, an applicant must obtain approval from the competent national authority of a EU member state in which the clinical trial is to be conducted. Furthermore, the applicant may only start a clinical trial after a competent ethics committee has issued a favorable opinion. A clinical trial application must be accompanied by an investigational medicinal product dossier with supporting information prescribed by the European Clinical Trials Directive and corresponding national laws of the member states and further detailed in applicable guidance documents. Similar approval requirements apply in the UK and a clinical trial application must be made to the UK regulatory authority (MHRA) prior to starting any clinical trial.

To obtain marketing approval of a product under EU regulatory systems, an applicant must submit a marketing authorization application, or MAA, either under a centralized or decentralized procedure. The centralized procedure provides for the grant of a single marketing authorization by the European Commission that is valid for all EU member states. The centralized procedure is compulsory for specific products, including for medicines produced by certain biotechnological processes, products designated as orphan medicinal products, advanced therapy medicinal products and products with a new active substance indicated for the treatment of certain diseases. For products with a new active substance indicated for the treatment of other diseases and products that are highly innovative or for which a centralized process is in the interest of patients, the centralized procedure may be optional.

Under the centralized procedure, the Committee for Medicinal Products for Human Use, or the CHMP, established at the EMA is responsible for conducting the scientific assessment of a product. The CHMP is also responsible for several post-authorization and maintenance activities, such as the assessment of modifications or extensions to an existing marketing authorization. For advanced therapy medicinal products (ATMPs), the scientific evaluation of MAA is primarily performed by the Committee for Advanced Therapies (CAT). The CAT prepares a draft opinion of each ATMP subject to a MAA which is sent for final approval to the CHMP.

22

Table of Contents

Under the centralized procedure in the EU, the maximum timeframe for the evaluation of an MAA is 210 days, excluding clock stops, when additional information or written or oral explanation is to be provided by the applicant in response to questions of the CHMP. Accelerated evaluation might be granted by the CHMP in exceptional cases, when a medicinal product is of major interest from the point of view of public health and in particular from the viewpoint of therapeutic innovation. In this circumstance, the EMA ensures that the opinion of the CHMP is given within 150 days. Then, the European Commission grants or refuses the marketing authorization, following a procedure that involves representatives of the member states. Although the CHMP's opinion is not binding, the Commission's decision to grant or refuse the market authorization is frequently in accordance with the CHMP's assessment except in very rare cases. For marketing approval in the U.K, an application for marketing approval will be made for the MHRA and follows a similar process to that used in the EU.

Marketing authorization is valid for five years in principle and the marketing authorization may be renewed after five years on the basis of a re-evaluation of the risk-benefit balance by the EMA or by the competent authority of the authorizing member state or in the U.K. To this end, the marketing authorization holder must provide the EMA or the competent authority with a consolidated version of the file in respect of quality, safety and efficacy, including all variations introduced since the marketing authorization was granted, at least six months before the marketing authorization ceases to be valid. Once renewed, the marketing authorization is valid for an unlimited period, unless the Commission or the competent authority decides, on justified grounds relating to pharmacovigilance, to proceed with one additional five-year renewal. Any authorization which is not followed by the actual placing of the drug on the EU market (in case of centralized procedure) or on the market of the authorizing member state within three years after authorization ceases to be valid (the so-called sunset clause).

As a result of Brexit, as of January 1, 2021, marketing authorizations granted on the basis of a centralized procedure in the EU are only valid in Northern Ireland, but not in Great Britain (England, Scotland and Wales). However, prior EU authorizations have all been automatically converted into U.K. marketing authorizations effective in Great Britain. UK rules require marketing authorization holders to be established in the U.K. or in the EU/European Economic Area. EU rules require marketing authorization holders to be established in the EU/European Economic Area and, in addition, that certain activities be performed in the EU, related for example to pharmacovigilance, batch release and quality control. Marketing authorization holders may need to take steps to comply with these requirements aiming at holding both a EU and a U.K. marketing authorization.

With regard to the sunset clause, from the perspective of the U.K, the period of three years during which the drug has not been marketed in Great Britain will be restarted from the date of conversion to a Great Britain marketing authorization. From the perspective of the EU, in case the drug has been marketed in the U.K, the placing on the U.K. market before the end of the Brexit transition period will be taken into account. If, after the end of the Brexit transition period, the drug is not placed on any other market of the remaining member states of the EU, the three year period for the sunset clause will start running from the last date the drug was placed on the U.K. market before the end of the Brexit transition period.

Legal Proceedings and Related Matters

From time to time, we may be party to litigation that arises in the ordinary course of our business. We do not have any pending litigation that, separately or in the aggregate, would, in the opinion of management, have a material adverse effect on our results of operations, financial condition or cash flows.

Employees and Human Capital Management

As of December 31, 2022, we had 534 employees. Of these employees, 407 were in research and development (including in manufacturing and operations, and quality control and quality assurance) and 127 were in management and administrative functions (including business development, finance, intellectual property, information technology and general administration). We have never had a work stoppage and none of our employees are covered by collective bargaining agreements or require representation by a labor union. In November 2022, we announced that, in addition to de-prioritizing non-core programs, we were also undertaking a headcount reduction of approximately 25% to 30%. The reduction was completed in Q1 2023 with an overall reduction of approximately 25%.

23

Table of Contents

We value our employees and as a company work hard to employ those individuals that will work with us to achieve the objectives of the Company and share our values. We engage with our employees in multiple ways including through companywide business meetings, social events and smaller team events. We employ individuals based on their experience and ability to perform the applicable job and encourage diversity in our workforce whenever possible. We have an equal opportunities policy which promotes the right of every employee to be treated with dignity and respect and not to be harassed or bullied on any grounds. We employ individuals from approximately 32 different nationalities within our U.K. and U.S. offices and are working to encourage diversity within our workforce. We have a Diversity and Inclusion Council with membership comprising diverse employees from all levels in the Company and a Diversity and Inclusion Plan has been created and championed across the business by the executive team and presented to the Board. D&I progress updates are reviewed regularly by the Board Remuneration Committee.

We have a performance-based reward scheme, bonus scheme and share option plan which all employees are entitled to participate in. These schemes and other employee incentive programs are designed to retain employees. Over 2022, the total global attrition rate was approximately 22%.

Other Information

​

The Company’s primary website is www.adaptimmune.com. Information in the investor section and on our website is not part of this Annual Report on Form 10-K or any of our other securities filings unless specifically incorporated herein or therein by reference. The Company makes available, free of charge, at its corporate website, its Annual Report on Form 10-K, quarterly reports on Form 10-Q, current reports on Form 8-K and amendments to those reports filed or furnished pursuant to Section 13(a) or 15(d) of the Securities Exchange Act of 1934, as amended (the “Exchange Act”), as soon as reasonably practicable after they are electronically filed with the Securities and Exchange Commission (“SEC”). The SEC maintains an internet site that contains reports, proxy and information statements and other information regarding issuers that file electronically with the SEC at www.sec.gov.

Item 1A. Risk Factors.

Our business has significant risks. You should carefully consider the following risk factors as well as all other information contained in this Annual Report, including our consolidated financial statements and the related notes, before making an investment decision regarding our securities. The risks and uncertainties described below are those material risk factors currently known and specific to us that we believe are relevant to our business, results of operations and financial condition. Additional risks and uncertainties not currently known to us or that we now deem immaterial may also impair our business, results of operations and financial condition.

Risk Factors Summary

The following is a summary of the principal risks that could adversely affect our business.

Risks Related to Our Financial Condition and Capital Requirements

Risks Related to the entry into a merger agreement with TCR² Therapeutics Inc.

​

​

24

Table of Contents

​

Risks Related to the Development of Our Cell Therapies

Risks Related to the Manufacture and Supply of Our Cell Therapies

Risks Related to the Commercialization and Marketing of Our Cell Therapies

Risks Related to the COVID-19 Pandemic

Risks Related to Government Regulation

25

Table of Contents

Risks Related to Our Reliance Upon Third Parties

Risks Related to Our Intellectual Property

General Business Risks

For a more complete discussion of the risks we face as a business, please see the discussion below.

Risks Related to Our Financial Condition and Capital Requirements

We have incurred net losses every year since our inception and expect to continue to incur net losses in the future.

We have generated losses since our inception in 2008, during which time we have devoted substantially all of our resources to research and development efforts relating to our cell therapies, including engaging in activities to manufacture and supply our cell therapies for clinical trials, conducting clinical trials of our cell therapies, providing general and administrative support for these operations, enhancing capabilities to support commercialization for ADP-A2M4 and protecting our intellectual property. For the years ended December 31, 2022, 2021 and 2020, we incurred net losses of $165.5 million, $158.1 million, and $130.1 million respectively. As of December 31, 2022, we had accumulated losses of $909.3 million. We do not have any products approved for sale and have not generated any revenue from product supplies or royalties. Based on our current plans, we do not expect to generate product or royalty revenues unless and until we obtain marketing approval for, and commercialize, any of our SPEAR T-cells or other cell therapies.

We are currently operating in a period of heightened economic uncertainty and capital markets volatility which has been significantly impacted by geopolitical instability, including the conflict between Russia and Ukraine, the continued impact of COVID-19 and high inflation globally which has materially adversely affected our ability to raise additional equity. These conditions have had and may continue to have a material adverse effect on our business, financial condition and results of operations.

26

Table of Contents

Economic uncertainty in various global markets, including the U.S. and Europe, caused by the COVID-19 pandemic and political instability, including the effects of Russia's invasion of Ukraine, have led to market disruptions, including significant increases in commodity prices, energy and fuel prices, credit and capital market instability and supply chain interruptions which have caused record inflation globally. As a result, central banks around the world have raised interest rates significantly and have signaled that they will continue to do so in an effort to fight inflation. Certain governments have also introduced additional measures to address rising inflation (including the Inflation Reduction Act in the U.S.) which may further impact investment into the biotechnology industry. This has led to significant volatility in capital markets which continues to limit our ability to raise funds and as a result has impacted our ability to conduct certain of our planned activities including the start of certain trials, progression of pre-clinical candidates into clinical trials and the speed with which we can manufacture and supply cell therapies for clinical trials. We have stopped certain non-core activities, including stopping enrolment in the SURPASS-2 trial and delaying the new clinical trials with our TIL-IL7 product and the next generation ADP-A2M4N7X19 cell therapy. We are also taking a number of further actions to extend our cash runway including a reduction of headcount by approximately 25% which we expect to complete in the first quarter of 2023. The reduction in headcount will affect our ability to progress our planned business activities, could result in a loss of individuals who are key to core business activities and will also impact the timing of commercialization for our afami-cel cell therapy product. We have also ceased investment in non-core programs including commercialization activities for afami-cel, the SURPASS-2 clinical trial, the TIL-IL7 clinical trial and certain of our preclinical programs. The full impact of these actions is not currently known but could result in skilled individuals leaving the Company which would further impact our ability to progress our business objectives. If these market conditions persist for a prolonged period of time, we could be required to take additional measures and potentially restructure the Company’s business. Any such disruptions may also magnify the impact of other risks and may impact our ability to realize value from our ongoing third-party collaborations or to perform those collaborations or other business activities as currently planned.

If we fail to obtain additional financing, we may be unable to complete the development and commercialization of our cell therapies.

We expect to continue incurring significant losses as we continue with our research and development programs and to incur general and administrative costs associated with our operations. The extent of funding required to develop our cell therapies is difficult to estimate given the novel nature of our cell therapies and their un-proven route to market and we may not have anticipated all the costs required to meet our planned objectives. As of December 31, 2022, the Company had cash and cash equivalents of $108.0 million, marketable securities of $96.6 million, and stockholders’ equity of $81.9 million. We expect to use these funds to advance and accelerate the clinical development of our cell therapies, to further develop and enhance our manufacturing capabilities and secure a commercially viable manufacturing platform for all of our cell therapies, to advance cell therapies through preclinical testing and progress such cell therapies through to clinical trials, to support commercialization for ADP-A2M4 and to fund working capital, including for other general corporate purposes. We believe that our cash and cash equivalents and marketable securities will be sufficient to fund our operations, based upon our currently anticipated research and development activities and planned capital spending, into early 2025. This belief is based on estimates that are subject to risks and uncertainties and may change if actual results differ from management’s estimates. Our expenses may increase significantly in the event of any of the following:

27

Table of Contents

We cannot be certain that additional funding will be available on acceptable terms, or at all. We have no committed source of additional capital and if we are unable to raise additional capital in sufficient amounts or on terms acceptable to us, we may have to significantly delay, scale back or discontinue the development or commercialization of our cell therapies or other research and development initiatives. Our license and supply agreements may also be terminated if we are unable to meet the payment obligations under these agreements. We could be required to seek collaborators for our cell therapies at an earlier stage than otherwise would be desirable or on terms that are less favorable to us than might otherwise be available or relinquish or license on unfavorable terms our rights to our cell therapies in markets where we otherwise would seek to pursue development or commercialization ourselves.

Our current cash projections include reliance on the ability to obtain certain tax credits and the operation of certain tax regimes within the U.K. Should these cease to be available, this could impact our ongoing requirement for investment and the timeframes within which additional investment is required.

As a company that carries out extensive research and development activities, we benefit from the U.K. research and development tax credit regime for small and medium sized companies, whereby our principal research subsidiary company, Adaptimmune Limited, is able to surrender the trading losses that arise from its research and development activities for a payable tax credit of up to approximately 33.4% of eligible research and development expenditures. Qualifying expenditures largely comprise employment costs for research staff, consumables and certain internal overhead costs incurred as part of research projects. Subcontracted research expenditures are eligible for a cash rebate of up to approximately 21.7%. The majority of our pipeline research, clinical trials management and manufacturing development activities, all of which are being carried out by Adaptimmune Limited, are eligible for inclusion within these tax credit cash rebate claims.

We may not be able to continue to claim research and development tax credits (R&D tax credits) or the amount we can claim may reduce in the future as we expand our business because we may no longer qualify as an SME (small or medium-sized enterprise) or as a result of announced changes to the UK R&D tax credit regime lowering the amount of tax credits SMEs can claim. In order to qualify as an SME for R&D tax credits, we must continue to be a company with

28

Table of Contents

fewer than 500 employees and also have either an annual turnover not exceeding €100 million or a balance sheet not exceeding €86 million. Once we no longer qualify for SME R&D tax credits, it is likely we would qualify for the U.K. research and development expenditure credit scheme (the “RDEC Scheme”) which is claimable by large companies. The cash credit rate for the RDEC Scheme is currently approximately 10.5% of qualifying expenditure in comparison to approximately 33.4% for SME R&D credits. In addition, the types of qualifying expenditure are more restricted under the RDEC Scheme, in that certain subcontracted costs can no longer qualify for relief. The U.K. government has introduced some changes to the U.K. research and development credit rules, which include potential restrictions in the eligibility of costs where research and development activities are performed overseas. These changes may give rise to a reduction in our U.K. research and development credit claims in the future.

We may also benefit in the future from the U.K.’s “patent box” regime, which would allow certain profits attributable to revenues from patented products to be taxed at a rate of 10%. As we have many different patents covering our products, future upfront fees, milestone fees, product revenues, and royalties could be taxed at this favorably low tax rate. When taken in combination with the enhanced relief available on our research and development expenditures, we expect a long-term lower rate of corporation tax to apply to us. If, however, there are unexpected adverse changes to the U.K. research and development tax credit regime or the “patent box” regime, or we are unable to qualify for such advantageous tax legislation, our business, results of operations and financial condition may be adversely affected.

Our ability to generate revenue from sales of our cell therapies and become profitable depends on our ability to progress our cell therapies through development.

We have no cell therapies approved for commercial sale, have not generated any revenue from sales of our cell therapies, and do not anticipate generating any revenue from sales of our cell therapies until sometime after we receive regulatory approval, if at all, for the commercial sale of a cell therapy. We may never become profitable.

Our ability to generate revenue and achieve profitability depends on many factors, including:

Risks Related to the entry into a merger agreement with TCR² Therapeutics Inc.

​

Our shareholders may not realize a benefit from transaction for the combination of us and TCR2 Therapeutics (“Merger”) commensurate with the ownership dilution they will experience in connection with the Merger.

​

29

Table of Contents

On March 5, 2023, we, CM Merger Sub, Inc., a Delaware corporation and our wholly-owned subsidiary (“Merger Sub”), and TCR² Therapeutics Inc. (“TCR² Therapeutics”), entered into the Agreement and Plan of Merger dated as of March 5, 2023 (the “Merger Agreement”), pursuant to which, among other things, and subject to the satisfaction or waiver of certain conditions set forth in the Merger Agreement, Merger Sub will merge with and into TCR² Therapeutics, with TCR² Therapeutics continuing as our wholly-owned subsidiary and the surviving corporation of the merger (the “Merger”).  If the combined company is unable to realize the full strategic and financial benefits currently anticipated from the Merger, our shareholders will have experienced substantial dilution of their ownership interests without receiving commensurate benefits, or only receiving part of the commensurate benefit to the extent the combined company is able to realize only part of the strategic and financial benefits currently anticipated from the Merger.

​

Failure to complete the Merger may result in either us or TCR² Therapeutics paying a termination fee to the other party and could significantly harm the market price of our ADSs and negatively affect the future business and operations of each company.

​

If the Merger is not completed and the Merger Agreement is terminated under certain circumstances, the terminating party may be required to pay the other party a termination fee of up to $2.4 million. Even if a termination fee or reimbursement of expenses of the other party are not payable in connection with a termination of the Merger Agreement, each of us and TCR² Therapeutics will have incurred significant fees and expenses, which must be paid whether or not the Merger is completed.  In addition, if the Merger Agreement is terminated and our board of directors determines to seek another business combination, there can be no assurance that we will be able to find a partner and close an alternative transaction on terms that are as favorable or more favorable than the terms set forth in the Merger Agreement.  In addition, if the Merger is not consummated our need to raise additional capital to fund our operations will increase and capital whether in the form of equity or debt financing may not be available to us on favorable terms or at all.

​

The issuance of our ordinary shares to TCR² Therapeutics stockholders pursuant to the Merger Agreement must be approved by our shareholders, and the Merger Agreement and transactions contemplated thereby must be approved by TCR² Therapeutics stockholders. Failure to obtain these approvals would prevent the closing of the Merger.

​

Before the Merger can be completed, our stockholders must approve, among other things, the issuance of our ordinary shares to TCR² Therapeutics stockholders pursuant to the Merger Agreement, and TCR² Therapeutics stockholders must adopt the Merger Agreement and approve the Merger and the related transactions. Failure to obtain the required shareholders approvals may result in a material delay in, or the abandonment of, the Merger. Any delay in completing the Merger may materially adversely affect the timing and benefits that we expect to achieve from the Merger.

​

Our shareholders will have a reduced ownership and voting interest in, and will exercise less influence over the management of, the combined company following the closing of the Merger as compared to their current ownership and voting interest in our company.

​

If the proposed Merger is completed, our current shareholders will own a smaller percentage of the combined company than their ownership in our company prior to the Merger. Immediately after the Merger, our pre-Merger shareholders and TCR² Therapeutics pre-Merger stockholders are expected to own approximately 75% and 25%, respectively, of our outstanding shares of the combined company.

​

During the pendency of the Merger, we may not be able to enter into a business combination with another party on more favorable terms because of restrictions in the Merger Agreement, which could adversely affect our business prospects.

​

Covenants in the Merger Agreement may impede our ability to make acquisitions during the pendency of the Merger, subject to specified exceptions or may alternatively require the consent of TCR² Therapeutics. As a result, if the Merger is not completed, we may be at a disadvantage to our competitors during such period. In addition, while the Merger Agreement is in effect, we are generally prohibited from soliciting, initiating or knowingly encouraging, inducing or facilitating any inquiries, indications of interest, proposals or offers that constitute or may reasonably be expected to lead

30

Table of Contents

to certain transactions involving a third party, including a merger, sale of assets or other business combination, subject to specified exceptions. Any such transactions could be favorable to our shareholders, but we may be unable to pursue them.

​

If the conditions to the Merger are not satisfied or waived, the Merger will not occur.

​

Even if the transactions contemplated by the Merger Agreement are approved by our shareholders and TCR² Therapeutics stockholders, certain other specified conditions set forth in the Merger Agreement must be satisfied, to the extent permitted by applicable law, or waived to complete the Merger, including approval from The Nasdaq Stock Market LLC (“Nasdaq”) to issue the ordinary shares underling the ADSs for the Merger consideration. We cannot be certain that all of the conditions will be satisfied or waived. If the conditions are not satisfied or waived, the Merger will not occur or will be delayed, and we may lose some or all of the intended benefits of the Merger.

​

Risks Related to the Development of Our Cell Therapies

We are heavily reliant on the data obtained from our ongoing ADP-A2M4CD8 clinical trials.

Our ability to obtain additional financing is dependent on the data from our ADP-A2M4CD8 (“SURPASS”, “SURPASS-2” and “SURPASS-3”) clinical trials among other factors. Data from any of these trials might not be sufficient to enable us to further develop ADP-A2M4CD8 or other cell therapies within the pipeline. If we do not see sufficiently positive data in any of these clinical trials or if we see an adverse side effect profile preventing continuation of any clinical trials, we may not be able to obtain the additional financing required to fund our anticipated business operations. This in turn may necessitate delays in planned activities, including the commercialization of ADP-A2M4 in synovial sarcoma and our ability to progress other cell therapies into and through clinical development.

Our cell therapy products require significant additional clinical testing before we can seek regulatory approval and begin commercialization.

Our cell therapies may not achieve regulatory approval or proceed to the next stage of development. All of our cell therapies require further clinical development before a BLA can be filed with any regulatory authority to permit commercialization. Results seen in early clinical trials, for example, with our ADP-A2M4, ADP-A2M4CD8, and ADP-A2AFP cell therapy candidates may not be predictive of the data we will obtain in our later phase clinical trials. Negative results in any cell therapy clinical program may also impact our ability to continue with clinical development of other similar cell therapies. Although each cell therapy may target a different cancer peptide or protein, the underlying technology platform and other aspects of our clinical programs are the same or substantially similar for many of our cell therapies. Accordingly, a failure or delay in any one program may affect the ability to obtain regulatory approval to continue or conduct clinical programs for other cell therapies.

The data produced in our ongoing clinical trials is at an early stage, and future data may not support continued progression of any of our therapies through development.

The patient response data that has been reported in our trials (excluding SPEARHEAD-1 in synovial sarcoma patients) represents data from small numbers of patients within each study at the applicable dosing level. As such, the data is initial data, and there is no assurance that any responses will persist, that we will see responses in any other patients or that such patients will not suffer severe adverse events which may result in a delay or halt to any clinical trial. Further data may be required in order to progress cell therapies to the next stage of development. Negative results in one clinical trial may also impact ability to proceed with development in other clinical trials given the common technology platform and similarity of other aspects of our clinical programs.

Like other biologic products, we expect there may be greater variability in results for cell therapies which are administered on a patient-by-patient basis than for “off-the-shelf” products, like many other biologics. There is typically an extremely high rate of attrition from the failure of any products proceeding through clinical trials. Cell therapies in later stages of clinical trials may fail to show the desired safety and efficacy profile despite having progressed through preclinical programs and initial clinical trials. A number of companies in the biopharmaceutical industry have suffered

31

Table of Contents

significant setbacks in advanced clinical trials due to lack of efficacy or unacceptable safety issues, notwithstanding promising results in earlier trials. Most biologic candidates that begin clinical trials are never approved by regulatory authorities for commercialization. We may therefore be unsuccessful in demonstrating the required efficacy and safety profile from the performance of any of our clinical programs.

We are aware that certain patients do not respond to our SPEAR T-cells and that other patients may relapse or cease to present the peptide being targeted by such SPEAR T-cells. The percentage of the patient population in which these events may occur is unknown, but the inability of patients to respond and the possibility of relapse may impact our or our collaborator’s ability to conduct clinical trials, to obtain regulatory approvals, if at all, and to successfully commercialize any SPEAR T-cell.

We plan to provide further data updates as and when the applicable data is believed to be sufficiently mature.  Given the nature of T-cell therapies and the time taken to observe patient responses to our SPEAR T-cells, we cannot provide any assurance that further data updates will be provided frequently or that such data updates will be available at any particular time.

We may not be able to commence additional clinical trials for cell therapies on the timeframes we expect.

Progression of new cell therapies into clinical trials is inherently risky and dependent on the results obtained in preclinical programs, the results of other clinical programs and any other activities which may impact our ability to commence clinical trials, for example, availability of manufacturing process and components. If any issues are identified during any cell therapy development, we may experience significant delays in development of pipeline candidates and in existing clinical programs. This may also impact our ability to achieve certain financial milestones and the expected timeframes to market any of our cell therapies.

The FDA or other regulatory authorities may not approve any IND (or equivalent application) for any of our future cell therapies, or for new indications for our cell therapies already in clinical trials, or may require amendments to existing protocols (including as a result of the COVID-19 pandemic). For example, we amended the protocols for all of our pending and on-going ADP-A2M4 and ADP-A2M10 clinical trials in response to reported serious adverse events (“SAEs”) of prolonged serious pancytopenia in our clinical trials for ADP-A2M4 and ADP-A2M10 in two patients treated with the highest lymphodepletion regimen. Such amendments and updates may delay our clinical trials, may require changes or resubmission of our INDs, or may result in or be related to a halt in our planned or contemplated clinical trials.

​

We conduct clinical trials at sites in the UK and European Union. This requires gaining the approval of country specific review bodies for GMO application and Clinical Trial Application (“CTA”). As this is not a harmonized process, the requirements can vary considerably, and delays can be incurred at a country level. For example, the information required in relation to manufacturing processes or assays may differ between countries and may require additional testing to be conducted in order for approval to be obtained.

T-cell therapy is a novel approach to cancer treatment that creates significant increased risk in terms of side-effect profile.

Development of a pharmaceutical or biologic therapy or product has inherent risks based on differences in patient population and responses to therapy and treatment. The mechanism of action and impact on other systems and tissues within the human body following administration of our cell therapies is complex and not completely understood, which means that we cannot predict the long-term effects of treatment with any of our cell therapies (whether by us or a collaborator). In addition, it is not possible for any pre-clinical safety package to completely identify all potential safety risks. For example, there is a risk that the target (or similar) peptide to which any SPEAR T-cell is directed may be present in both patients’ cancer cells and other non-cancer cells and tissues. Cross-reactivity or allo-reactivity (binding to peptides presented on other HLA types) could also occur where the affinity-enhanced engineered TCR contained within any cell therapy including SPEAR T-cells binds to peptides presented by HLAs other than the HLA type for which the relevant TCR was developed. Should any of these cross-reactivities occur, patients may suffer a range of side effects associated with the SPEAR T-cell binding to both the cancer cells and/or other cells and tissues and such side effects

32

Table of Contents

could cause patient death. The extent of these side effects will depend on which cells and tissues are affected as well as the degree to which the target (or similar) peptide is expressed in these cells and tissues.

Any unacceptable toxicities arising in ongoing clinical programs could result in suspension or termination of those clinical programs. The more SAEs that are reported the greater the risk of suspension of termination of clinical programs, even where the SAEs are unrelated to each other or to our cell therapies. Our patients undergo lymphodepletion prior to receiving our SPEAR T-cells which leaves them immuno-compromised for a period of time after the lymphodepletion and increases their risk of contracting other unrelated diseases or pathogens including COVID-19. The treatment regimen used in our protocols, in particular the use of chemotherapy, also carries an inherent risk of cytopenia (including pancytopenia), where blood cell levels reduce to lower than normal. If blood cell levels do not recover sufficiently the patient may suffer serious adverse events, which may even be life threatening. There have been multiple events of pancytopenia as well as SAEs similar to those reported across our clinical trials; these are multifactorial in etiologies and could result in regulatory authorities imposing a hold on one or more clinical programs whilst the events are investigated further. Serious adverse events seen with other immunotherapy products, such as the severe cytokine release syndrome (“CRS”) and neurotoxicity events observed with CD19-directed CAR-T cell treatments, may also occur at any stage of the clinical program. Further, following infusion of any SPEAR T-cells, there may be a transient inflammatory reaction of the disease to the treatment. Symptoms in any given subject would be dependent on the location and other characteristics of their tumor. For example, subjects with lung tumors may experience dyspnea. Cardiac toxicities may be observed in patients with pre-existing cardiac or pericardial masses. These inflammatory reactions and related symptoms may be mild and self-limited, but can be severe, potentially life-threatening and require medical intervention.

Any side effects may also result in the need to perform additional trials, which will delay regulatory approval for such cell therapies and require additional resources and financial investment to bring the relevant cell therapy to market.

Use of cell therapies in combination with other third party products or therapies may increase or exacerbate side effects that have been seen with our cell therapies alone or may result in new side effects that have not previously been identified with our cell therapies alone. Any undesirable side effects seen in combination trials may affect our ability to continue with and obtain regulatory approval for the combination therapy, but may also impact our ability to continue with and obtain regulatory approval for our cell therapies alone.

Summary information on adverse events seen in relation to each of our cell therapies are provided below based on data cuts as of the dates stated. Where we have become aware of material safety events after the date of any data cut, a description of such events is also included.

​

Adverse events occurring in >10% of subjects considered by investigators to be at least possibly related to ADP-A2M4 include CRS, pyrexia, neutropenia/neutrophil count decreased, fatigue, leukopenia/WBC decreased, lymphopenia/ lymphocyte count decreased, nausea, rash, sinus tachycardia/tachycardia, chills, headache, thrombocytopenia/platelet count decreased, decreased appetite, hypotension, febrile, neutropenia dyspnea and hypophosphataemia. Serious adverse event (SAEs), considered by investigators to be at least possibly related to ADP-A2M4, were reported for 32 (25%) subjects under the program.  These events include CRS, empyema, sepsis, pleural effusion, pneumothorax, pulmonary embolism, pyrexia, anemia, aplastic anemia, pancytopenia, cerebrovascular accident, encephalopathy, neurotoxicity, arrhythmia, alanine aminotransferase increased, aspartate aminotransferase increased, blood alkaline phosphatase increased, platelet count decreased, lymphoproliferative disorder, deep vein thrombosis, superior vena cava occlusion, acute kidney injury,  pulmonary hemorrhage, white blood cell count decreased and rash.  Two of these subjects have had treatment related fatal SAEs: one patient experienced pancytopenia/aplastic anemia and the other experienced a cerebrovascular accident (stroke).

​

33

Table of Contents

For the 13 patients in long term follow-up, one case of thrombocytopenia/Platelet count decreased and one case of CRS were reported as related to ADP-A2M4. No related SAEs were reported.

​

​

In the SURPASS study, there have been 43 patients treated with ADP-A2M4CD8 monotherapy. The adverse events occurring in >10%  of patients treated with ADP-A2M4CD8 monotherapy (n=43) and considered by investigators to be at least possibly related to ADP-A2M4CD8 include CRS, neutropenia/neutrophil count decreased, anemia/red blood cell count decreased, fatigue, pyrexia, rash, thrombocytopenia/platelet count decreased, dyspnea, hypoxia, immune effector cell-associated neurotoxicity syndrome (ICANS), leukopenia/ white blood cell count decreased, pleural effusion, febrile neutropenia, and lymphopenia/ lymphocyte count decreased. SAEs, considered by investigators to be at least possibly related to ADP-A2M4CD8 monotherapy, were reported for 21 (48.8%) patients in the study.  These events include CRS, ICANS, anemia, pancytopenia, infusion related reaction, pyrexia, hypoxia, dyspnea, drug reaction with eosinophilia and systemic symptoms (DRESS Syndrome), rash, small intestinal obstruction, device related infection, pneumonia, blood creatinine increased and tumor lysis syndrome. Two of these patients had treatment-related fatal SAEs: one patient experienced pancytopenia and the other experienced CRS.

​

In the SURPASS-2 study (ADP-0055-002), there have been 3 patients treated with ADP-A2M4CD8 monotherapy. The adverse events considered by investigators to be at least possibly related to ADP-A2M4CD8 include rash, sciatica, CRS, pyrexia and respiratory failure. CRS was the only SAE considered by investigators to be at least possibly related to ADP-A2M4CD8 monotherapy.

​

In addition, there have been 3 patients treated with nivolumab in combination with ADP-A2M4CD8. The nivolumab combination group had a similar safety profile as the monotherapy group but is based on a small sample size with limited follow-up at this data cut off.

​

Across all ADP-A2M4CD8 trials, 27 total patients treated with ADP-A2M4CD8 monotherapy continue in long term follow up as at date of data cut-off. No related AE/SAEs were reported.

​

We may encounter substantial delays in our clinical trials or may not be able to conduct our trials on the timelines we expect.

Any delay in our clinical trials will impact our ability to obtain clinical data from those trials and our ability to progress our business along anticipated timelines and to raise capital. Delays in clinical trials can also increase the costs incurred in performing those clinical trials or necessitate a need to initiate additional clinical trial sites. Our ability to progress our clinical trials is dependent on a number of factors including:

34

Table of Contents

Even if we are able to enroll a sufficient number of patients in our clinical trials, delays in patient enrollment may result in, and have resulted in, increased costs or may affect the timing or outcome of the planned clinical trials,

35

Table of Contents

which could prevent completion of these trials and adversely affect our ability to advance the development of our SPEAR T-cells and other cell therapies.

Certain of our clinical trials include dose escalation studies in which the dose of cell therapies administered to patients is varied or initial studies in which the pre-treatment regimen may be varied, for example, a regimen with and without fludarabine. The outcome of such dose escalation or initial studies will inform the clinical study going forward. However, the need to carry out dose escalation or other initial studies may result in delays in data from such clinical programs while the most suitable dose or regimen is assessed. For example, the trial design for our SPEAR T-cell trials includes dose escalation and therefore efficacy data may not be obtained from initial patients treated in such studies during the dose escalation phase.

Our cell therapies represent a novel approach to cancer treatment that could result in heightened regulatory scrutiny and delays in clinical development.

Use of any of our cell therapies to treat a patient involves genetically engineering a patient’s T-cells. This is a novel treatment approach that carries inherent development risks including the following, any of which can result in delays to our ability to develop our cell therapies:

36

Table of Contents

Our clinical trials may fail to demonstrate adequately the safety and efficacy of any cell therapies which would prevent or delay regulatory approval and commercialization.

There is a risk in any clinical trial that side effects from cell therapies will require a hold on, or termination of, clinical programs or further adjustments to clinical programs in order to progress any cell therapy. Our cell therapy must demonstrate an acceptable benefit:risk profile in its intended patient population and for its intended use. The benefit:risk profile required for product licensure will vary depending on these factors and may include not only the ability to show tumor shrinkage, but also adequate duration of response, a delay in the progression of the disease and/or an improvement in survival. For example, response rates from the use of the SPEAR T-cells may not be sufficient to obtain regulatory approval unless we or our collaborators can also show an adequate duration of response.

The regulatory authorities (including the FDA) may issue a hold on our clinical trials as a result of safety information and data obtained in third party clinical trials or in relation to third party products. Any such hold will require addressing by us and will inevitably delay progression of the clinical trials concerned, if such clinical trials progress at all.

In addition, even if such trials are successfully completed, the FDA or foreign regulatory authorities may not interpret the results as we or our collaborators do. Accordingly, more trials may be required before we can submit any cell therapy for regulatory approval. To the extent that the results of the trials are not satisfactory to the FDA or foreign regulatory authorities for support of a marketing authorization application, we may be required to expend significant resources, which may not be available to us, to conduct additional trials in support of potential approval of our cell therapies. We cannot predict whether any of our cell therapies will satisfy regulatory requirements at all or for indications in which such cell therapies are currently being evaluated as part of any clinical programs.

We have limited experience conducting later stage clinical trials which may cause a delay in any clinical program and in the obtaining of regulatory approvals.

Although we have recruited a team that has significant experience with clinical trials, as a company we have limited experience in conducting clinical trials through to regulatory approval. In part because of this lack of experience, we cannot be certain that planned clinical trials will begin or be completed on time, if at all. Large-scale trials would require significant additional financial and management resources, and reliance on third-party clinical investigators, contract research organizations, or CROs, or consultants. Relying on third-party clinical investigators, consultants or CROs may force us to encounter delays that are outside of our control.

Clinical trials are expensive, time-consuming and difficult to implement.

Clinical trials, depending on the stage, can be costly as well as difficult to implement and define, particularly with technologies that are not tried and tested, such as our cell therapies. These factors can lead to a longer clinical development timeline and regulatory approval process, including a requirement to conduct further or more complex

37

Table of Contents

clinical trials in order to obtain regulatory approval. Regulatory authorities may disagree with the design of any clinical program, and designing an acceptable program could lead to increased timeframes for obtaining of approvals, if any. In addition, progression of clinical trials depends on the ability to recruit suitable patients to those trials and delay in recruiting will impact the timeframes of such clinical trials and as a result the timeframes for obtaining regulatory approval, if any, for the relevant cell therapy.

In particular, eligible patients must be screened for the target peptide and HLA type, which may reduce the number of patients who can be recruited for any clinical program. For example, low target peptide expression levels in the NY-ESO SPEAR T-cell and ADP-A2M10 programs affected speed of patient recruitment in certain of the clinical trials. The ability to administer cell therapies to patients in accordance with set protocols for the clinical trials and the results obtained depends on patient participation for the duration of the clinical trial, which many of these patients are unable to do because of their late-stage cancer and limited life expectancy.

Validation of our cell therapies requires access to human samples which we may be unable to obtain or, if they can be obtained, that the terms under which they are provided will be favorable to us.

​

Certain of the steps involved in validating and carrying out safety testing in relation to our cell therapies require access to human samples (e.g., tissues samples or cell samples) from third parties. Such samples may be obtained from universities or research institutions and will often be provided subject to certain terms and conditions. We may not be able to obtain samples in sufficient quantities to enable preclinical testing in sufficient quantities for planned activities, particularly during the period in which COVID-19 impacts the ability of research institutions to supply and access such samples. In addition, the terms under which such samples are available may not be acceptable to us or may restrict our use of any generated results or require us to make payments to the third parties.

Our cell therapies and their application are not fully scientifically understood and are still undergoing validation and investigation.

Cell therapies including our SPEAR T-cells and their potential associated risks are still under investigation. Our cell therapies including our SPEAR T-cells may not work in the way that we currently anticipate and affinity modification of the receptors within T-cells or other cellular therapies may not produce the anticipated enhancements in activity. For example, there is a potential risk that, given that the TCR chains in our SPEAR T-cells are produced separately and then assembled within patient T-cells into full TCRs, the TCR chains from both transduced and naturally occurring T-cells could be assembled into an unintended end TCR due to mispairing of TCR chains, which could create unknown recognition and cross-reactivity problems within patients. Although this phenomenon has not been reported in humans, it remains a theoretical risk for our SPEAR T-cells and other similar cell therapies and is still being studied and investigated. This could delay regulatory approval, if any, for the relevant cell therapy. To the extent that any mispairing is identified, either in our or our competitors’ clinical trials, additional investment may be required in order to modify relevant cell therapies and to further assess and validate the risk of such mispairing to patients. Following modification of the relevant SPEAR T-cell or other cell therapy, such modified cell therapy may not remain suitable for patient treatment and may not eliminate the risk of mispairing of TCR chains and regulatory approval may not be obtained on a timely basis or at all in relation to such modified cell therapy. The occurrence of such events would significantly harm our business, prospects, financial condition and results of operations.

We may not be able to identify and validate additional target peptides or isolate and develop affinity-enhanced TCRs or other cell therapy candidates that are suitable for validation and further development.

The success of our cell therapies depends on both the identification of target peptides presented on cancer cells, which can be bound by our cell therapy products, and isolation and affinity enhancement of receptors including TCRs, which can be used to treat patients if regulatory approval is obtained. Any failure to identify and validate further target peptides will reduce the number of potential cell therapies that we can successfully develop, which in turn will reduce the commercial opportunities available to us and increase our reliance on our existing SPEAR T-cells. Delays in our ability to identify and develop target peptides and cell therapies, including as caused by COVID-19 or similar pandemics, may also impact our ability to progress development of programs and obtain additional funds to support our business.

38

Table of Contents

We may not develop new cell therapy candidates for which the safety and efficacy profiles enable progression to and through preclinical testing and into clinical development. Failure to identify further candidates for progression into preclinical testing and clinical programs will significantly impact our pipeline of cell therapies and also increase our reliance on the SPEAR T-cells currently in clinical development. If resources become limited or if we fail to identify suitable target peptides, receptors including TCRs or affinity-enhanced receptors, our ability to submit INDs for further cell therapies may be delayed or never realized, which would have a materially adverse effect on our business.

Development of an “off-the-shelf” cell therapy takes a considerable amount of time and such development may not be successful.

We have a platform process which may enable us to treat patient populations with an “off-the-shelf” product. However, our research program may not be successful, might not be carried out within the timescales currently anticipated, or even if successful might not result in a cell therapy that can be used to treat patients or achieve a profitable return on investment. In particular the various cell lines developed during this process will need to be properly characterized and produced in accordance with regulatory requirements and this development process can take a significant amount of time and resource to ensure that any process or cell lines can be used for the production of clinical stage and ultimately commercial stage products. For example, we have taken a decision to change the cell line being used to develop our MAGE-A4 allogeneic cell therapy due to the presence of a chromosomal abnormality in the original cell line provided by Universal Cells under our Agreement with them. It is not known at this time whether the cell therapy candidates resulting from the process will have a similar profile of activity to our existing cell therapy products or whether such cell therapy candidates will be safe to administer to patients. Delays may occur at any part of the process, including obtaining results during development that necessitate a requirement to repeat or modify steps in the process.

Risks Related to the Manufacture and Supply of Our Cell Therapies

Manufacturing and supply of cell therapies is complex, and if we encounter any difficulties in manufacture or supply of cell therapies our ability to provide supply of our cell therapies for clinical trials or for commercial purposes could be delayed or stopped.

The process of manufacturing and administering cell therapies is complex and highly regulated. The manufacture of cell therapies requires the harvesting of white blood cells from the patient, isolating certain T-cells from these white blood cells, combining patient T-cells with our lentiviral delivery vector through a process known as transduction, expanding the transduced T-cells to obtain the desired dose, and ultimately infusing the modified T-cells back into the patient. As a result of the complexities, our manufacturing and supply costs are likely to be higher than those at more traditional manufacturing processes and the manufacturing process is less reliable and more difficult to reproduce.

Delays or failures in the manufacture of cell therapies (whether by us, any collaborator or our third party contract manufacturers) can result in a patient being unable to receive their cell therapy or a requirement to re-manufacture which itself then causes delays in manufacture for other patients. Any delay or failure or inability to manufacture on a timely basis can adversely affect a patient’s outcomes and delay the timelines for our clinical trials. Such delays or failure or inability to manufacture can result from:

39

Table of Contents

40

Table of Contents

We have insurance to cover certain business interruption events which is capped at £10 million in the U.K. and $5 million in the U.S. However, because our level of insurance is capped, it may be insufficient to fully compensate us if any of these events were to occur in the future.

Our manufacturing process needs to comply with regulations, and any failure to comply with relevant regulations could result in delays in or termination of our clinical programs and suspension or withdrawal of any regulatory approvals.

In order to commercially produce our products, we will need to comply with the FDA’s and other regulatory authorities’ cGMP requirements at our Navy Yard facility, vector facility and third party contract manufacturing facilities. We may encounter difficulties in achieving quality control and quality assurance and may experience shortages in qualified personnel. We and our third party contract manufacturers are subject to inspections by the FDA and comparable agencies in other jurisdictions to confirm compliance with applicable regulatory requirements once the process has been approved. Any failure to follow cGMP or other regulatory requirements, reliably manufacture product or delay, interruption or other issues that arise in the manufacture, fill-finish, packaging, or storage of our cell therapies as a result of a failure of our facilities or the facilities or operations of third parties to comply with regulatory requirements or pass any regulatory authority inspection could significantly impair our ability to develop and commercialize our cell therapies, including leading to significant delays in the availability of our cell therapies for our clinical trials or the termination of or suspension of a clinical trial, or the delay or prevention of a filing or approval of marketing authorization applications for our cell therapies. Significant non-compliance could also result in the imposition of sanctions, including warning letters, fines, injunctions, civil penalties, failure of regulatory authorities to grant marketing approvals for our cell therapies, delays, suspension or withdrawal of approvals, license revocation, seizures or recalls of products, operating restrictions and criminal prosecutions, any of which could damage our reputation and our business.

Given we now manufacture cell therapies at our own U.S. manufacturing facility and our allogeneic facility in the UK, and lentiviral vectors at a dedicated U.K. vector facility, regulatory authorities might raise non-compliance issues or require us to make changes to the way in which we operate our facilities. This may result in a delay in our ability to manufacture cell therapies at our own facility or in our ability to supply vector material for use in the manufacturing process. In addition, any cell therapy or vector produced in any of our facilities might not be able to meet regulatory requirements and we may be unable to recruit and maintain sufficient staff to enable manufacture of products within required timescales. Resourcing of cell manufacturing facilities is increasingly competitive, which may restrict the number of available skilled operators which can be recruited at our manufacturing facilities. Any failure to meet regulatory requirements or produce cell therapies and vector according to regulatory requirements could result in delays to our clinical programs, potential side effects and even fatalities to patients and may result in withdrawal of regulatory approval for our manufacturing facility.

We have our own manufacturing capabilities which may result in increased costs being incurred by us.

During 2017, we opened a manufacturing facility for our SPEAR T-cell products within our Navy Yard facility in Philadelphia, Pennsylvania and have started manufacturing SPEAR T-cells for use in our clinical trials. Regulatory

41

Table of Contents

authorities, in particular the FDA, might not continue to approve our ability to manufacture SPEAR T-cells or other cell therapies at the Navy Yard facility. We opened a manufacturing facility in the UK for our off-the-shelf cell therapies in 2022 and manufacture of cell therapies at that facility will require the obtaining of regulatory approval and maintenance of the regulatory approval once obtained.

Our ability to successfully manufacture our own cell therapies at our facilities within a reasonable period of time and within currently projected costs is dependent on a number of factors including:

Any delay or failure in manufacture at our facility could result in delays to the supply of cell therapies for our clinical programs. Should any of our third party manufacturers also cease to be able to or be unable to supply cell therapies at a time where our own manufacturing facility is unable to produce cell therapies for use in our clinical programs or is unable to produce cell therapies at the required level, then we will be unable to support such clinical programs until alternative manufacturing capability is secured.

Our autologous cell therapy products are patient-specific and we need to ensure that the correct product is administered to the correct patient.

Administration of cell therapies is patient-specific. The process requires careful handling of patient-specific products and fail-safe tracking to ensure that the tracking process is without error and that patient samples are tracked from patient removal, through manufacturing and re-administration to the same patient. While such mechanisms are in place, should the tracking process fail, whether at our own facility, a third party facility or at any point in the manufacturing and supply process, a patient could receive another patient’s T-cells resulting in significant toxicity and potentially patient fatality. We will need to invest in enhanced systems, such as bar coding, to further ensure fail safe tracking. There is always a risk of a failure in any such system. Inability to develop or adopt an acceptable fail-safe tracking methodology and handling regime may delay or prevent us from receiving regulatory approval and/or result in significant toxicity and potentially patient fatality if a patient receives another patient’s T-cells. This risk may be increased where cell therapies are used in clinical programs that we do not control or sponsor and, should an error be made in the administration of our cell therapies in such clinical programs, this could affect the steps required in our own clinical programs and manufacturing process requiring the addition of further tracking mechanisms to ensure fail-safe tracking. The tracking systems required to further ensure safe patient administration may also require increased administration to satisfy other regulatory requirements, for example, data protection requirements in Europe. The need to

42

Table of Contents

ensure tracking systems are adequate and to comply with these additional regulatory requirements may result in delay to the start of trials or the need to obtain additional regulatory licenses or consents prior to starting such trials.

Risks Related to the COVID-19 pandemic

The outbreak of COVID-19 and its variants or any other similar pandemic may materially delay development of our cell therapies and our ability to obtain additional financing.

​

The outbreak of coronavirus, SARS-CoV-2 (“COVID-19”) has developed into a global pandemic, spreading to most regions of the world including the U.S., U.K. and areas of Europe where we have facilities or ongoing clinical trials. Whilst impacts if the pandemic are reducing, should new strains be identified that are highly infectious or which cause serious side effects our business could be affected in the following ways:

​

​

The COVID-19 pandemic continues to evolve and the extent to which it may impact our future business is highly uncertain and difficult to predict. The impact on global health systems, the life sciences industry more generally or the economy as a whole is not yet known. Depending on the length and progression of such pandemic, we may experience disruptions that would significantly impact our business.

​

43

Table of Contents

Risks Related to the Commercialization and Marketing of Our Cell Therapies

We may not be able to obtain marketing approvals of our cell therapies as broadly as planned or on the timescales we plan.

The process of obtaining marketing approvals, both in the U.S. and in countries outside of the U.S., is expensive, may take many years and can vary substantially based upon a variety of factors, including the type, complexity and novelty of the cell therapies involved. For example, clinical trials may be required in pediatric populations before any marketing approval can be obtained, which can be time consuming and costly. Changes in marketing approval policies during the development period, changes in or the enactment of additional statutes or regulations, or changes in regulatory review for each submitted product application, may cause delays in the approval or rejection of an application. The FDA and foreign regulatory authorities also have substantial discretion in the drug and biologics approval process. The number and types of preclinical programs and clinical trials that will be required for regulatory approval varies depending on the cell therapy, the disease or condition that the cell therapy is designed to address, and the regulations applicable to any particular cell therapy. Approval policies, regulations or the type and amount of clinical data necessary to gain approval may change during the course of a cell therapy’s clinical development and may vary among jurisdictions, and there may be varying interpretations of data obtained from preclinical programs or clinical trials, either of which may cause delays or limitations in the approval or the decision not to approve an application.

In addition, approval of our cell therapies could be delayed or refused for many reasons, including the following:

44

Table of Contents

Our estimates of the patient population that may be treated by our cell therapies is based on estimates informed by published information. This information may not be accurate in relation to our cell therapies and our estimates of potential patient populations could therefore be much higher or lower than those that are actually available or possible for commercialization. In addition, these estimates are based on assumptions about the number of eligible patients which have the peptide and HLA type targeted by the applicable cell therapy. Different patient populations will present different peptides according to their specific HLA type. HLA types vary across the patient population and, due to this variability, any therapy will initially only be suitable for treatment of patients expressing the particular HLA type presenting the relevant peptide.

We have begun submission of a BLA for afami-cel, but the review and approval of this BLA may not occur on the anticipated timelines, and we cannot be certain that the FDA will grant final marketing approval.

We began submitting modules of a BLA for afami-cel for the treatment of synovial sarcoma in December 2022, and we plan to complete the rolling submission by mid-2023. The BLA submission for afami-cel is supported by positive clinical data from the SPEARHEAD-1 clinical trial in patients with advanced synovial sarcoma. We anticipate that the application will be eligible for Priority Review under the FDA's Regenerative Medicine Advanced Therapy (“RMAT”) program.

However, approval of this BLA can be delayed or denied by the FDA for several reasons, including but not limited to those outlined above. In particular, the FDA may conclude that the data submitted in support of the BLA are insufficient to demonstrate a favorable benefit:risk profile in the proposed patient population without the submission of additional information or data, which could require the conduct of additional clinical studies and the resubmission of the BLA.

Development of a commercially available cell therapy process is difficult, and we may be unable to develop the process on currently anticipated timescales or at all.

Developing a commercially viable process is a difficult and uncertain task, and there are risks associated with scaling to the level required for advanced clinical trials or commercialization, including, among others, requirements to characterize the manufacturing process, increased costs, potential problems with process scale-out, process reproducibility, stability issues, lot consistency, loss of product, and timely availability of reagents or raw materials or contract manufacturing services or facilities. A failure to develop such a commercially viable process within anticipated timescales may prevent or delay progression of our T-cell therapies into pivotal clinical trials and ultimately commercialization. This failure to develop a timely process may result from, for example, inability to scale-up within required timelines, inability to put in place the required processes and control measures for a commercial process or failure of third parties (including vector suppliers) to put in place adequate facilities or processes to enable commercial manufacture. In addition, we may ultimately be unable to reduce the expenses associated with our SPEAR T-cells to levels that will allow us to achieve a profitable return on investment.

45

Table of Contents

Following grant of marketing authorization we will be subject to ongoing regulatory obligations, which may result in significant additional expense as well as significant penalties if we fail to comply with regulatory requirements or experience unanticipated problems with our cell therapies.

If the FDA or a comparable foreign regulatory authority approves our cell therapies, the manufacturing processes, labeling, packaging, distribution, adverse event reporting, storage, advertising, promotion, import, export and recordkeeping for our cell therapies will be subject to extensive and ongoing regulatory requirements. These requirements include submissions of safety and other post-marketing information and reports, registration and listing, as well as continued compliance with cGMPs and cGCPs for any clinical trials that we conduct post-approval. We and our contract manufacturers will be subject to periodic unannounced inspections by the FDA to monitor and ensure compliance with cGMPs. We must also comply with requirements concerning advertising and promotion for any cell therapies for which we obtain marketing approval. Promotional communications with respect to prescription drugs, including biologics, are subject to a variety of legal and regulatory restrictions and must be consistent with the information in the product’s approved labeling. Thus, we will not be able to promote any cell therapies we develop for indications or uses for which they are not approved.

We may not be able to develop or obtain approval for the analytical assays and companion diagnostics required for commercialization of our cell therapies including ADP-A2M4.

Administration of our cell therapies requires the use of an immuno-chemistry or other screening assay in which patients are screened for the presence of the cancer peptide targeted by our cell therapies. For example, in our ADP-A2M4 trial patients are screened for the presence of MAGE-A4. This assay requires the identification of suitable antibodies which can be used to identify the presence of the relevant target cancer peptide. Our patients are also screened for their HLA-type as only patients with certain HLA-types can receive our cell therapies.

If safe and effective use of a biologic product depends on an in vitro diagnostic, such as a test to detect patients with a particular cancer peptide, then the FDA generally requires approval or clearance of the diagnostic, known as a companion diagnostic, concurrently with approval of the therapeutic product. To date, the FDA has generally required in vitro companion diagnostics that are intended for use in selection of patients who will respond to cancer treatment to obtain a pre-market approval, or PMA, which can take up to several years, for that diagnostic approval or clearance to occur simultaneously with approval of the biologic product.

We expect that, for all our cell therapies, the FDA and similar regulatory authorities outside of the U.S. will require the development and regulatory approval of a companion diagnostic assay as a condition to approval. We also expect that the FDA may require PMA supplemental approvals for use of that same companion diagnostic as a condition of approval of additional cell therapies. We do not have experience or capabilities in developing or commercializing these companion diagnostics and plan to rely in large part on third parties to perform these functions.

If we or our collaborators, or any third parties that we engage to assist us, are unable to successfully develop companion diagnostic assays for use with any SPEAR T-cells, or are unable to obtain regulatory approval or experience delays in either development or obtaining regulatory approval (including as a result of the impact of the COVID-19 pandemic), we may be unable to identify patients with the specific profile targeted by the relevant cell therapy for enrollment in our clinical trials. In addition, delay in development and approval of any companion diagnostic (including as a result of the impact of the COVID-19 pandemic) may also impact our ability to obtain a marketing approval for the therapeutic product and to commercialize the therapeutic product. For example, delays in the development of a companion diagnostic for detection of the MAGE-A4 antigen in synovial sarcoma and MRCLS indications may result in delays to any marketing approval for ADP-A2M4 in those indications. Accordingly, further investment may be required to further develop or obtain the required regulatory approval for the relevant companion diagnostic assay, which would delay or substantially impact our ability or our collaborators’ ability to conduct further clinical trials or obtain regulatory approval.

46

Table of Contents

Obtaining and maintaining regulatory approval of our cell therapies in one jurisdiction does not mean that we will be successful in obtaining regulatory approval of our cell therapies in other jurisdictions.

We or our collaborators may submit marketing authorization applications in multiple countries. Regulatory authorities in different countries have different requirements for approval of cell therapies with which we must comply prior to marketing in those jurisdictions. Obtaining foreign regulatory approvals and compliance with foreign regulatory requirements could result in significant delays, difficulties and costs for us and could delay or prevent the introduction of our cell therapies in certain countries. For example, in certain jurisdictions additional clinical trials in different patient populations may be required. If we fail to comply with the regulatory requirements in international markets and/or receive applicable marketing approvals, our target market will be reduced and our ability to realize the full market potential of our cell therapies will be harmed.

The market opportunities for cell therapies may be limited to those patients who have failed prior treatments.

Initial approval of new cancer therapies may be limited to what is referred to as third-line use. Third-line treatment is the third type of treatment following initial, or first-line, treatment and second-line treatment, which is given when first-line treatment does not work or ceases working. However, cancer therapies may be used from the point at which cancer is detected in its early stages (first-line) onward. Whenever the first-line therapy fails or the process is unsuccessful, second-line therapy may be administered, such as additional rounds of chemotherapy, radiation and antibody drugs or a combination of these treatments. If second-line therapies fail, patients are generally given the opportunity to receive third-line therapies, which tend to be more novel therapies. Our current clinical trials generally require that patients have received chemotherapy prior to enrollment and are primarily directed to third-line use. Depending upon the outcome of current trials, we or our collaborators may conduct future clinical trials using cell therapies for first-line therapy, but clinical trials might not be approved or if approved such trials might not lead to regulatory approval. If our cell therapies only receive third-line or second-line approval, the patient population into which we or our collaborators can supply our cell therapies will be significantly reduced, which may limit commercial opportunities.

In addition, our patient population may be derived from those who have previously failed checkpoint therapy, which may result in tumor resistance mechanisms which also impart resistance to our cell therapies and hence may reduce the effectiveness of our cell therapies.

We currently have a limited marketing and sales organization and have no experience in marketing products.

As an organization, we have never marketed or supplied commercial pharmaceutical or biologic products or therapies. We will need to transition from a company with a research and development focus to a company capable of supporting commercial activities. We may not be successful in such a transition.

We do not currently have a sales force and will need to hire and develop the sales function and associated support network if we are to supply cell therapies on a commercial basis. As our cell therapies proceed through clinical programs, we intend to develop an in-house marketing organization and sales force, which will require significant capital expenditures, management resources, and time. We will have to compete with other pharmaceutical and biotechnology companies to recruit, hire, train, and retain suitably skilled and experienced marketing and sales personnel. This process may result in additional delays in bringing our cell therapies to market or in certain cases require us to enter into alliances with third parties in order to do so. However, there can be no assurance that we will be able to establish or maintain such collaborative arrangements, or even if we are able to do so, that they will result in effective sales forces. Any revenue we receive will depend upon the efforts of such third parties, which may not be successful. We may have little or no control over the marketing and sales efforts of such third parties, and our revenue from cell therapy sales may be lower than if we had commercialized our cell therapies ourselves. We also face significant competition in our search for third parties to assist us with the sales and marketing efforts of our cell therapies. Such competition may also result in delay or inability to supply cell therapies to particular countries or territories in the world which in turn will restrict the revenue that can be obtained from any cell therapy. Any inability on our part to develop in-house sales and commercial distribution capabilities or to establish and maintain relationships with third-party collaborators that can successfully

47

Table of Contents

commercialize any cell therapy in the U.S. or elsewhere will have a materially adverse effect on our business and results of operations.

If product liability lawsuits are brought against us, we may incur substantial liabilities and may be required to limit commercialization of our cell therapies.

We face an inherent risk of product liability as a result of the clinical testing of our cell therapies and our ongoing manufacture of cell therapies and will face an even greater risk upon any commercialization. For example, we may be sued if any of our SPEAR T-cells causes or is perceived to cause injury or is found to be otherwise unsuitable during clinical testing, manufacturing, marketing or sale. Any such product liability claims may include allegations of defects in manufacturing, defects in design, a failure to warn of dangers inherent in the product, negligence, strict liability or a breach of warranties. Claims could also be asserted under state consumer protection acts. If we cannot successfully defend ourselves against product liability claims, we may incur substantial liabilities or be required to limit commercialization of our cell therapies. Even a successful defense would require significant financial and management resources and, regardless of the merits or eventual outcome, liability claims may result in:

Our inability to obtain sufficient product liability insurance at an acceptable price to protect against potential product liability claims could also prevent or inhibit the commercialization of our cell therapies. We currently hold £15.0 million in clinical trial insurance coverage in the aggregate per year, with a per trial limit of £5.0 million. We also hold products and services liability insurance capped at £5.0 million in the aggregate and public liability insurance capped at £5.0 million per occurrence. These levels may not be adequate to cover all liabilities that we may incur. We may also need to increase our insurance coverage as we expand the scope of our clinical trials and commercialize any of our cell therapies. In addition, insurance coverage is increasingly expensive. We may not be able to maintain insurance coverage at a reasonable cost or in an amount adequate to satisfy any liability that may arise.

48

Table of Contents

Even if we or our collaborators obtain regulatory approval of our cell therapies, they may not gain market acceptance among physicians, patients, hospitals, cancer treatment centers and others in the medical community.

The use of engineered T-cells and cell therapies more generally as a potential cancer treatment is a recent development and may not become broadly accepted by physicians, patients, hospitals, cancer treatment centers and others in the medical community. Additional factors will influence whether SPEAR T-cells are accepted in the market, including:

In addition, although we are not utilizing embryonic stem cells or replication competent vectors in our manufacturing process, adverse publicity due to the ethical and social controversies surrounding the therapeutic use of such technologies, and reported side effects from any clinical trials using these technologies or the failure of such trials to demonstrate that these therapies are safe and effective may limit market acceptance of cell therapies including SPEAR T-cells. If our cell therapies are approved but fail to achieve market acceptance among physicians, patients, hospitals, cancer treatment centers or others in the medical community, we or our collaborators will not be able to generate significant revenue.

Even if our cell therapies achieve market acceptance, we or our collaborators may not be able to maintain that market acceptance over time if new products or technologies are introduced that are more favorably received than our cell therapies, are more cost effective or render our cell therapies obsolete.

Coverage, price flexibility, and reimbursement may be limited or unavailable in certain market segments for cell therapies.

Successful sales of cell therapies, if approved, depend on the availability of coverage and adequate reimbursement from third-party payors. In addition, because cell therapies represent new approaches to the treatment of

49

Table of Contents

cancer, we cannot accurately estimate the potential revenue from cell therapies. Patients who are provided medical treatment for their conditions generally rely on third-party payors to reimburse all or part of the costs associated with their treatment. Obtaining coverage and adequate reimbursement from governmental healthcare programs, such as Medicare and Medicaid, and commercial payors is critical to new product acceptance.

Government authorities and third-party payors, such as private health insurers and health maintenance organizations, decide which drugs and treatments they will cover and the amount of reimbursement. Reimbursement by a third-party payor may depend upon a number of factors, including, but not limited to, the third-party payor’s determination that use of a product is:

Obtaining coverage and reimbursement approval of a cell therapy from a government or other third-party payor is a time-consuming and costly process which could require us to provide to the payor supporting scientific, clinical and cost-effectiveness data for the use of our products. Even if we obtain coverage for a given cell therapy, the resulting reimbursement payment rates might not be adequate for us to achieve or sustain profitability or may require co-payments that patients find unacceptably high. Patients are unlikely to use cell therapies unless coverage is provided and reimbursement is adequate to cover a significant portion of the cost of the cell therapy.

In the U.S., no uniform policy of coverage and reimbursement for products exists among third-party payors. Therefore, coverage and reimbursement for products can differ significantly from payor to payor. As a result, the coverage determination process is often a time-consuming and costly process that will require us to provide scientific and clinical support for the use of our cell therapies to each payor separately, with no assurance that coverage and adequate reimbursement will be obtained.

In some foreign countries, particularly those in the EU, the pricing of biologics is subject to governmental control. In these countries, pricing negotiations with governmental authorities can take considerable time after obtaining marketing approval of a cell therapy. In addition, market acceptance and sales of our cell therapies will depend significantly on the availability of coverage and adequate reimbursement from third-party payors for the cell therapies and may be affected by existing and future health care reform measures.

There have been, and likely will continue to be, legislative and regulatory proposals at the foreign, national and state levels directed at broadening the availability of healthcare and containing or lowering the cost of healthcare, including the Affordable Care Act (ACA) or provisions of the Inflation Reduction Act (IRA). Such regulatory changes may bring prescription drug pricing reform or healthcare affordability programs that, for example, seek to lower prescription drug costs by allowing governmental healthcare programs to negotiate prices with drug companies, put an inflation cap on drug prices, and lower out-of-pocket expenses for recipients of governmental healthcare programs. We cannot predict the initiatives that may be adopted in the future. The continuing efforts of the government, insurance companies, managed care organizations and other payors of healthcare services to contain or reduce costs of healthcare and/or impose price controls may adversely affect:

50

Table of Contents

Any reduction in reimbursement from Medicare or other government programs may result in a similar reduction in payments from private payors, which may adversely affect our future profitability.

Our cell therapies for which we intend to seek approval as biologic products may face competition sooner than anticipated.

The enactment of the Biologics Price Competition and Innovation Act of 2009, or BPCIA, created an abbreviated pathway for the approval of biosimilar and interchangeable biological products. The abbreviated regulatory pathway establishes legal authority for the FDA to review and approve biosimilar biologics, including the possible designation of a biosimilar as “interchangeable” based on its similarity to an existing reference product. Under the BPCIA, an application for a biosimilar product cannot be approved by the FDA until 12 years after the original branded product or “reference” is approved under a BLA. On March 6, 2015, the FDA approved the first biosimilar product under the BPCIA. However, the law is complex and is still being interpreted and implemented by the FDA and as a result, its ultimate impact, implementation and meaning are subject to uncertainty. While it is uncertain when such processes intended to implement BPCIA may be fully adopted by the FDA, any such processes could have a material adverse effect on the future commercial prospects for our biological products.

There is a risk that the FDA will not consider our cell therapies to be reference products for purposes of 12-year reference product exclusivity, potentially creating the opportunity for biosimilar competition sooner than anticipated. Additionally, this period of regulatory exclusivity does not apply to companies pursuing regulatory approval via their own full BLA, rather than via the abbreviated biosimilar pathway. Moreover, the extent to which a biosimilar, once approved, will be substituted for any one of our reference products in a way that is similar to traditional generic substitution for non-biological drug products is not yet clear, and will depend on a number of marketplace and regulatory factors that are still developing.

Foreign countries also have abbreviated regulatory pathways for biosimilars and hence even where the FDA does not approve a biosimilar biologic, a biosimilar could be approved using an abbreviated regulatory pathway in other markets where our cell therapies are approved and marketed.

Risks Related to Government Regulation

Regulatory authorities may impose a hold on our clinical trials.

A clinical trial may be suspended or terminated by us or a collaborator, IRBs for the institutions in which such trials are being conducted, the Data Monitoring Committee for such trial, or by the FDA or other regulatory authorities due to a number of factors, including failure to conduct the clinical trial in accordance with regulatory requirements or our clinical protocols, inspection of the clinical trial operations or trial site by the FDA or other regulatory authorities resulting in the imposition of a clinical hold, unforeseen safety issues or adverse side effects, failure to demonstrate a benefit from using a cell therapy, changes in governmental regulations or administrative actions or lack of adequate funding to continue the clinical trial. If we or our collaborators experience termination of, or delays in the completion of, any clinical trial of our cell therapies, the commercial prospects for our cell therapies will be harmed, and our ability to generate product revenue will be delayed. In addition, any delays in completing our clinical trials will increase our costs, slow our product development and approval process and jeopardize our ability to commence product sales and generate revenue.

51

Table of Contents

The FDA regulatory process can be difficult to predict, in particular whether for example, accelerated approval processes are available or further unanticipated clinical trials are required will depend on the data obtained in our ongoing clinical trials.

The regulatory approval process and the amount of time it takes us to obtain regulatory approvals for our cell therapies will depend on the data that are obtained in our ongoing clinical trials and in one or more future registration or pivotal clinical trials. We may attempt to seek approval on a per indication basis for our cell therapies on the basis of a single pivotal trial or on the basis of data from a Phase 2 trial. While the FDA requires in most cases two adequate and well-controlled pivotal clinical trials to demonstrate the efficacy of a product candidate, a single trial with other confirmatory evidence may be sufficient where the trial is a large multicenter trial demonstrating internal consistency and a statistically very persuasive finding of a clinically meaningful effect on mortality, irreversible morbidity or prevention of a disease with a potentially serious outcome and confirmation of the result in a second trial would be practically or ethically difficult. Depending on the data we obtain, the FDA or other regulatory authorities may require additional clinical trials to be carried out or further patients to be treated prior to the granting of any regulatory approval for marketing of our cell therapies. It is difficult for us to predict with such a novel technology exactly what will be required by the regulatory authorities in order to take our cell therapies to market or the timeframes under which the relevant regulatory approvals can be obtained. In December 2022, Congress passed FDORA, which made changes to the Accelerated Approval program, and it is unclear how those changes may impact our ability to obtain or maintain regulatory approval via the Accelerated Approval program.

Obtaining and maintaining regulatory approval of our cell therapies in one jurisdiction does not mean that we will be successful in obtaining regulatory approval of our cell therapies in other jurisdictions.

Obtaining and maintaining regulatory approval of our cell therapies in one jurisdiction does not guarantee that we or our collaborators will be able to obtain or maintain regulatory approval in any other jurisdiction, while a failure or delay in obtaining regulatory approval in one jurisdiction may have a negative effect on the regulatory approval process in others. For example, even if the FDA grants marketing approval of a SPEAR T-cell, comparable regulatory authorities in foreign jurisdictions must also approve the manufacturing, marketing and promotion of the SPEAR T-cell in those countries. Approval procedures vary among jurisdictions and can involve requirements and administrative review periods different from, and greater than, those in the U.S., including additional preclinical programs or clinical trials as clinical trials conducted in one jurisdiction may not be accepted by regulatory authorities in other jurisdictions. In many jurisdictions outside the U.S., a cell therapy must be approved for reimbursement before it can be approved for sale in that jurisdiction. In some cases, the price that we or our collaborators intend to charge for our cell therapies is also subject to approval.

We may be unable to obtain breakthrough or similar designations for our cell therapies or maintain the benefits associated with such designations.

In 2012, the FDA established a Breakthrough Therapy designation which is intended to expedite the development and review of products that treat serious or life-threatening diseases when “preliminary clinical evidence indicates that the drug may demonstrate substantial improvement over existing therapies on one or more clinically significant endpoints, such as substantial treatment effects observed early in clinical development.” The designation of a SPEAR T-cell as a Breakthrough Therapy provides potential benefits that include more frequent meetings with the FDA to discuss the development plan for the SPEAR T-cell and ensure collection of appropriate data needed to support approval; more frequent written correspondence from the FDA about things such as the design of the proposed clinical trials and use of biomarkers; intensive guidance on an efficient drug development program, beginning as early as Phase 1; organizational commitment involving senior managers; and eligibility for rolling review and Priority Review.

We have obtained RMAT designation (Regenerative Medicine Advanced Therapy designation) from the FDA for ADP-A2M4 for the treatment of synovial sarcoma. We may apply for similar status or accelerated programs in other countries and for other of our products and indications. However, given the novel nature of our cell therapies, it is difficult for us to predict whether the FDA or other regulatory authorities will approve such requests or what further clinical or other data may be required to support an application for such accelerated approval procedures.

52

Table of Contents

Breakthrough Therapy designation does not change the standards for product approval. Additionally, other treatments from competing companies may obtain the designations and impact our ability to develop and commercialize our SPEAR T-cells, which may adversely impact our business, financial condition or results of operation.

We may also seek Accelerated Approval under the FDA’s Fast Track And Accelerated Approval programs, the FDA may approve a drug or biologic for a serious or life-threatening illness that provides meaningful therapeutic benefit to patients over existing treatments based upon a surrogate endpoint that is reasonably likely to predict clinical benefit, or on a clinical endpoint that can be measured earlier than irreversible morbidity or mortality, that is reasonably likely to predict an effect on irreversible morbidity or mortality or other clinical benefit, taking into account the severity, rarity, or prevalence of the condition and the availability or lack of alternative treatments. For drugs granted Accelerated Approval, post-marketing confirmatory trials have been required to describe the anticipated effect on irreversible morbidity or mortality or other clinical benefit. These confirmatory trials must be completed with due diligence. Moreover, the FDA may withdraw approval of our cell therapy or indication approved under the accelerated approval pathway if, for example:

The FDA’s Accelerated Approval program has come under increased scrutiny in recent years from both internal and external stakeholders have raised concerns that confirmatory trials have not been completed or have not demonstrated intended effect. Recent legislation (FDORA) has increased the FDA’s authority to impose more stringent requirements on the timing and conduct of confirmatory trials, and on the FDA’s ability to expedite the withdrawal from approval of a biological product when confirmatory trials have not been completed or do not show intended effect.

In Europe, the EMA has implemented the so-called "PRIME" (Priority Medicines) status in order support the development and accelerate the approval of complex innovative medicinal products addressing an unmet medical need. The PRIME status enables early dialogue with the relevant EMA scientific committees and, possibly, some payers; and thus reinforces the EMA's scientific and regulatory support. It also opens accelerated assessment of the marketing authorization application (150 days instead of 210 days). The PRIME status, which is decided by the EMA, is reserved to medicines that may benefit from accelerated assessment, i.e. medicines of major interest from a public health perspective, in particular from a therapeutic innovation perspective.

In 2020, the EMA granted access to the PRIME initiative to ADP-A2M4 for the treatment of certain patients with synovial sarcoma. We may apply for PRIME status for other of our cell therapy products. There can be no assurance that any application will be successful in obtaining PRIME status.

We will be subject to ongoing regulatory obligations and continued regulatory review, which may result in significant additional expense as well as significant penalties if we fail to comply with regulatory requirements or experience unanticipated problems with our cell therapies.

Any regulatory approvals that we receive for our cell therapies will require surveillance to monitor the safety and efficacy of the cell therapy. The FDA may also require a risk evaluation and mitigation strategy in order to approve

53

Table of Contents

our cell therapies, which could entail requirements for a medication guide, physician communication plans or additional elements to ensure safe use, such as restricted distribution methods, patient registries and other risk minimization tools.

Later discovery of previously unknown problems with our cell therapies, including adverse events of unanticipated severity or frequency, or with our third-party manufacturers or manufacturing processes, or failure to comply with regulatory requirements, may result in, among other things:

The FDA’s and other regulatory authorities’ policies may change, and additional government regulations may be enacted that could prevent, limit or delay regulatory approval of our cell therapies. We cannot predict the likelihood, nature or extent of government regulation that may arise from future legislation or administrative action, either in the U.S. or abroad. If we are slow or unable to adapt to changes in existing requirements or the adoption of new requirements or policies, or if we are not able to maintain regulatory compliance, we may lose any marketing approval that we may have obtained and we may not achieve or sustain profitability.

In addition, if following any pivotal clinical trial we were able to obtain accelerated approval of any of our cell therapies, the FDA will require us to conduct a confirmatory trial or trials to verify the predicted clinical benefit and additional safety studies. The results from the confirmatory trial or trials may not support the clinical benefit, which would result in the approval being withdrawn.

54

Table of Contents

We may seek a conditional marketing authorization in Europe for some or all of our current cell therapies, but we may not be able to obtain or maintain such authorization.

As part of its marketing authorization process, the EMA may grant marketing authorizations for certain categories of medicinal products on the basis of less complete data than is normally required, when doing so may meet unmet medical needs of patients and serve the interest of public health. In such cases, it is possible for the Committee for Medicinal Products for Human Use, or CHMP, to recommend the granting of a marketing authorization, subject to certain specific obligations to be reviewed annually, which is referred to as a conditional marketing authorization. This may apply to medicinal products for human use that fall under the centralized procedure (EMA's scientific assessment and European Commission's approval), including those that aim at the treatment, the prevention, or the medical diagnosis of seriously debilitating diseases or life-threatening diseases and those designated as orphan medicinal products.

A conditional marketing authorization may be granted when the CHMP finds that, although comprehensive clinical data referring to the safety and efficacy of the medicinal product have not been supplied, all the following requirements are met:

The granting of a conditional marketing authorization is restricted to situations in which only the clinical part of the application is not yet fully complete. Incomplete preclinical or quality data may only be accepted if duly justified and only in the case of a product intended to be used in emergency situations in response to public-health threats. Conditional marketing authorizations are valid for one year, on a renewable basis. The holder will be required to complete ongoing trials or to conduct new trials with a view to confirming that the benefit-risk balance is positive. In addition, specific obligations may be imposed in relation to the collection of pharmacovigilance data.

Granting a conditional marketing authorization allows medicines to reach patients with unmet medical needs earlier than might otherwise be the case and will ensure that additional data on a product are generated, submitted, assessed and acted upon. Although we may seek a conditional marketing authorization for one or more of our cell therapies, the CHMP may ultimately not agree that the requirements for such conditional marketing authorization have been satisfied. This would delay the commercialization of our cell therapies as we would have to wait for a complete data package before submitting the marketing authorization application.

We or our collaborators may not be able to obtain or maintain orphan drug exclusivity for our cell therapies.

Regulatory authorities in some jurisdictions, including the U.S. and Europe, may designate drugs or biologics for relatively small patient populations as orphan drugs. Orphan drug designation does not convey any advantage in or shorten the duration of the regulatory review and approval process, but it can lead to financial incentives, such as opportunities for grant funding toward clinical trial costs, tax advantages in-lieu of R&D tax credits and user-fee waivers.

Generally, if a product with an orphan drug designation subsequently receives the first marketing approval for the indication for which it has such designation, the product is entitled to a period of marketing exclusivity, which precludes the EMA or the FDA from approving another marketing authorization application for the same drug for that time period. The applicable period is seven years in the U.S. and ten years in Europe. The European exclusivity period can be reduced to six years if a drug no longer meets the criteria for orphan drug designation or if the drug is sufficiently profitable so that market exclusivity is no longer justified. Orphan drug exclusivity may be lost if the FDA determines

55

Table of Contents

that the request for designation was materially defective or if the manufacturer is unable to assure sufficient quantity of the drug to meet the needs of patients with the rare disease or condition. In addition, a competitor could avoid our orphan drug exclusivity, if its products is shown to be clinically superior. In Europe, the orphan exclusivity may be lost vis-à-vis another drug in cases the manufacturer is unable to assure sufficient quantity of the drug to meet patient needs or if that other product is proved to be clinically superior to the approved orphan product. Generally, the clinical superiority standards in the U.S. and in Europe are similar, and a product is clinically superior if it shows greater efficacy, greater safety, or makes a major contribution to patient care.

As a result of Brexit, as of January 1, 2021, incentives related to an orphan designation granted in the EU are limited to the EU and Ireland, but not Great Britain (England, Wales and Scotland). The competent authority in the U.K. (MHRA) will review applications for orphan designation at the time of a marketing authorization, and has announced that it will offer incentives in the form of market exclusivity and full or partial refunds for marketing authorization fees to encourage the development of medicines in rare diseases.

There can be no assurance that any of our cell therapies will be eligible for orphan drug designation in the U.S. or in other jurisdictions or that it will obtain orphan drug exclusivity upon approval or that we will not lose orphan drug designation for ADP-A2M4. Inability to obtain orphan drug designation for a specific cell therapy or loss of such designation for ADP-A2M4 in the future would prevent any ability to take advantage of the financial benefits associated with orphan drug designation and would preclude us from obtaining marketing exclusivity upon approval, if any. Even if we obtain orphan drug exclusivity for a product, that exclusivity may not effectively protect the product from competition because different drugs can be approved for the same condition.

The FDA’s interpretation of the scope of orphan drug exclusivity has been the subject of recent litigation in the Eleventh Circuit Court of Appeals. In the Catalyst case, the appellate court concluded that the FDA has impermissibly narrowed the scope of orphan exclusivity to the approved indication or use, rather than the broader disease or condition which was the basis of the orphan drug designation. The FDA has announced that it will continue to follow its existing regulations, notwithstanding the court decision. However, it is possible or even likely that additional litigation may arise, and there is considerable uncertainty about the scope of any orphan drug exclusivity that our products may be awarded.

Any failure by us to comply with existing regulations could harm our reputation and operating results.

The production of cell therapies is highly regulated and subject to constant inspection. The regulatory environment may also change from time to time. Any failure to comply with regulatory requirements, whether in the U.S. or in other countries in which our cell therapies are supplied, may result in investigation by regulatory authorities, suspension of regulatory authorizations and, as a result, suspension of clinical programs or ability to supply any of our cell therapies and potentially significant fines or other penalties being imposed in relation to any breach. Any failure may also harm our reputation and impact our ability going forward to obtain regulatory approvals for other cell therapies or require us to undertake additional organizational changes to minimize the risk of further breach. A failure to comply may apply to any part of our business, for example, to the processes used for manufacture of our cell therapies (including the reliability of the process) or to the processes used for treatment of patients (including tracking of patient product and supply of patient-specific product).

Our research and development activities utilize hazardous, radioactive and biological materials. Should such materials cause injury or be used other than in accordance with applicable laws and regulations, we may be liable for damages.

We use hazardous and biological reagents and materials in our research and development at our U.K. site. We have obtained the appropriate certification or ensured that such certification has been obtained as required for the use of these reagents but our use is subject to compliance with applicable laws and there is a risk that should any third party or employee suffer injury or damage from radioactive, hazardous or biological reagents that we may incur liability or obligations to compensate such third parties or employees. We have employer’s liability insurance capped at £10.0 million per occurrence and public liability insurance capped at £5.0 million per occurrence; however, these amounts may be insufficient to compensate us if these events actually occur in the future.

56

Table of Contents

We are subject to the U.K. Bribery Act, the U.S. Foreign Corrupt Practices Act and other anti-corruption laws, as well as export control laws, customs laws, sanctions laws and other laws governing our operations. If we fail to comply with these laws, we could be subject to civil or criminal penalties, other remedial measures, and legal expenses, which could adversely affect our business, results of operations and financial condition.

Our operations are subject to anti-corruption laws, including the U.K. Bribery Act 2010, or Bribery Act, the U.S. Foreign Corrupt Practices Act, or FCPA, and other anti-corruption laws that apply in countries where we do business. The Bribery Act, the FCPA and these other laws generally prohibit us and our employees and intermediaries from bribing, being bribed or making other prohibited payments to government officials or other persons to obtain or retain business or gain some other business advantage. Under the Bribery Act, we may also be liable for failing to prevent a person associated with us from committing a bribery offense. We and our commercial partners may operate in a number of jurisdictions that pose a high risk of potential Bribery Act or FCPA violations, and we participate in collaborations and relationships with third parties whose actions, if non-compliant, could potentially subject us to liability under the Bribery Act, FCPA or local anti-corruption laws. In addition, we cannot predict the nature, scope or effect of future regulatory requirements to which our international operations might be subject or the manner in which existing laws might be administered or interpreted.

We are also subject to other laws and regulations governing our international operations, including regulations administered by the governments of the U.K. and the U.S., and authorities in the EU, including applicable export control regulations, economic sanctions on countries and persons, anti-money laundering laws, customs requirements and currency exchange regulations, collectively referred to as the Trade Control laws.

However, there is no assurance that we will be completely effective in ensuring our compliance with all applicable anti-corruption laws, including the Bribery Act, the FCPA or other legal requirements, including Trade Control laws. If we are not in compliance with the Bribery Act, the FCPA and other anti-corruption laws or Trade Control laws, we may be subject to criminal and civil penalties, disgorgement and other sanctions and remedial measures, and legal expenses, which could have an adverse impact on our business, financial condition, results of operations and liquidity. Likewise, any investigation of any potential violations of the Bribery Act, the FCPA, other anti-corruption laws or Trade Control laws by U.K., U.S. or other authorities could also have an adverse impact on our reputation, our business, results of operations and financial condition.

If we are found in violation of federal or state “fraud and abuse” or other health care laws, we may be required to pay a penalty and/or be suspended from participation in federal or state health care programs, which may adversely affect our business, financial condition and results of operations.

If we obtain marketing approval for our products in the U.S., if at all, we will be subject to various federal and state health care “fraud and abuse” and other health care laws. Healthcare providers, physicians and third-party payors play a primary role in the recommendation and use of pharmaceutical products that are granted marketing approval. Accordingly, arrangements with third-party payors, existing or potential customers and referral sources are subject to broadly applicable fraud and abuse and other healthcare laws and regulations, and these laws and regulations may constrain the business or financial arrangements and relationships through which manufacturers market, sell and distribute the products for which they obtain marketing approval.

Such restrictions under applicable federal and state healthcare laws and regulations include the following the Anti-Kickback Statute, the Healthcare Reform Act, the False Claims Act, or FCA, federal criminal laws that prohibit executing a scheme to defraud any healthcare benefit program or making false statements relating to healthcare matters; the Physician Payment Sunshine Act, the Health Insurance Portability and Accountability Act of 1996 (HIPAA)

Violation of any of the laws described above or any other governmental laws and regulations may result in penalties, including civil and criminal penalties, damages, fines, the curtailment or restructuring of operations, the exclusion from participation in federal and state healthcare programs and imprisonment. Furthermore, efforts to ensure that business activities and business arrangements comply with applicable healthcare laws and regulations can be costly for manufacturers of branded prescription products. Additionally, if we are found in violation of one or more of these laws our business, results of operations and financial condition may be adversely affected.

57

Table of Contents

The U.K.’s withdrawal from the EU may adversely impact our and our collaborators’ ability to obtain regulatory approvals of our drug candidates in the U.K. and EU and may require us to incur additional expenses to develop, manufacture and commercialize our drug candidates in the U.K. and EU.

​

We are headquartered in the U.K. The U.K. formally exited the EU, commonly referred to as Brexit, on January 31, 2020. Under the terms of its departure, the U.K. entered a transition period, or the Transition Period, during which it continued to follow all EU rules, which ended on December 31, 2020. On December 30, 2020, the U.K. and EU signed the EU-UK Trade and Cooperation Agreement (“TCA”), which includes an agreement on free trade between the two parties and has been provisionally applicable since January 1, 2021.

​

Since January 1, 2021 the U.K. has operated under a separate regulatory regime to the European Union. European Union laws regarding medicinal products only apply in respect of the U.K. to Northern Ireland (as set out in the Protocol on Ireland/Northern Ireland). The EU laws that have been transposed into U.K. law through secondary legislation remain applicable. While the U.K. has indicated a general intention that new law regarding the development, manufacture and commercialization of medicinal products in the U.K. will align closely with EU law there are limited detailed proposals for future regulation of medicinal products. The TCA includes specific provisions concerning medicinal products, which include the mutual recognition of Good Manufacturing Practice, or GMP, inspections of manufacturing facilities for medicinal products and GMP documents issued (such mutual recognition can be rejected by either party in certain circumstances), but does not foresee wholesale mutual recognition of U.K. and EU pharmaceutical regulations including in relation to batch testing and pharmacovigilance, which remain subject to further negotiation. Therefore, there remains political and economic uncertainty regarding to what extent the regulation of medicinal products will differ between the U.K. and the EU in the future.

Since a significant proportion of the regulatory framework in the U.K. applicable to our business and our drug candidates is derived from European Union directives and regulations, the withdrawal has and could continue to materially impact the regulatory regime with respect to the development, manufacture, importation, approval and commercialization of our cell therapies in the U.K. or the European Union. Great Britain is no longer covered by the European Union’s procedures for the grant of marketing authorizations (Northern Ireland is covered by the centralized authorization procedure and can be covered under the decentralized or mutual recognition procedures). A separate marketing authorization will be required to market drugs in Great Britain. It is currently unclear whether the Medicines and Healthcare products Regulatory Agency in the U.K.is sufficiently prepared to handle the increased volume of marketing authorization applications that it is likely to receive. Any delay in obtaining, or an inability to obtain, any marketing approvals, as a result of Brexit or otherwise, would prevent us and our collaborators or delay us in commercializing any of our products in the UK and/or the EU and may restrict our ability to generate revenue and achieve sustainable profitability.

Following Brexit, there is no pre-marketing authorization orphan designation in Great Britain, instead an application for orphan designation is made at the same time as an application for marketing authorization. Orphan designation in the U.K. (or Great Britain, depending on whether there is a prior centralized marketing authorization in the EEA) following Brexit based on the prevalence of the condition in Great Britain as opposed to the current position where prevalence in the EU is the determinant. It is therefore possible that conditions that are currently designated as orphan conditions in the U.K., or Great Britain, will no longer be and that conditions are not currently designated as orphan conditions in the European Union will be designated as such in the U.K., or Great Britain.

There is a degree of uncertainty regarding the overall impact that Brexit will have in the long-term on the development, manufacturing and commercialization of pharmaceutical products, including the process to obtain regulatory approval in the U.K. for drug candidates and the award of exclusivities that are normally part of the European Union legal framework (for instance Supplementary Protection Certificates, Pediatric Extensions or Orphan exclusivity). Any divergence between the regulatory environments in place in the European Union and the U.K. could lead to increased costs and delays in bringing drug candidates to market.

Given certain regulatory authorizations within the EU can only be held by entities located in the EU, we have set up an EU subsidiary, Adaptimmune B.V.. This subsidiary currently holds orphan designation for our ADP-A2M4 product. We have also set up a third party to act as a qualified person to release product for use in the EU and ensure we can continue to treat patients in our EU clinical trials. Additional resources and requirements may be required to enable us to

58

Table of Contents

continue to hold required authorizations including marketing authorization in the EU and to commercialize our cell therapies in the EU.

In addition, we may be required to pay taxes or duties or be subjected to other hurdles in connection with the importation of our drug candidates into the European Union, or we may incur expenses in establishing a manufacturing facility in the EU to circumvent such hurdles, all of which may make our doing business in the EU and the EEA more difficult. If any of these outcomes occur, we may be forced to restrict or delay efforts to seek regulatory approval in the U.K. or the EU for our drug candidates, or incur significant additional expenses to operate our business, which could significantly and materially harm or delay our ability to generate revenues or achieve profitability of our business.

​

As a result of Brexit, other European countries may seek to conduct referenda with respect to their continuing membership with the European Union. Given these possibilities and others we may not anticipate, as well as the absence of comparable precedent, it is unclear what financial, regulatory and legal implications the withdrawal of the U.K. from the European Union will have in the long-term and how such withdrawal will affect us, and the full extent to which our business could be adversely affected.

Risks Related to Our Reliance Upon Third Parties

We rely on Universal Cells Inc. and Genentech Inc. in relation to the performance of collaboration agreements between us for the further development of ‘off-the-shelf’ cell therapies.

Development of allogeneic T-cell therapies and our ability to commercialize those allogeneic T-cell therapies may depend heavily on the performance of Universal Cells under the ongoing collaboration (the "Universal Cells Collaboration"), performance of Genentech under the ongoing collaboration (the “Genentech Collaboration”) and payments made by our collaborators to us in relation to such development. In particular:

​

59

Table of Contents

We rely heavily on ThermoFisher and the technology that we license from them.

The ability to use the ThermoFisher Dynabeads® CD3/CD28 technology to isolate, activate and expand T-cells is important to our ongoing ability to offer SPEAR T-cells. In December 2012, we entered into a series of license and sub-license agreements with Life Technologies Corporation (now part of ThermoFisher Scientific Inc. (“Thermofisher”)), such agreements having been amended as of November 2019. These agreements provide us with a field-based non-exclusive license under certain intellectual property rights owned or controlled by ThermoFisher in relation to the methods of use of the ThermoFisher Dynabeads® CD3/CD28 technology to isolate, activate and expand T-cells and enable transfection of the T-cells with any TCR genes to manufacture our TCR products and use and sell those TCR products to treat cancer, infectious disease and/or autoimmune disease. We also have a field-based non-exclusive sub-license under certain other patents which cover the method of use of the Dynabeads® CD3/CD28 and are controlled by ThermoFisher under a head-license from the University of Michigan, the United States Navy and the Dana-Farber Cancer Institute.

In June 2016, we entered into a supply agreement with ThermoFisher for the supply of the Dynabeads® CD3/CD28 technology. The supply agreement runs until December 31, 2025.

ThermoFisher has the right to terminate the above described agreements for material breach or insolvency. On termination of the license agreements, the supply agreement will also automatically terminate. If ThermoFisher terminates the non-exclusive license, sub-license and supply agreements or otherwise refuses or is unable to supply the Dynabeads® product, we will have to seek an alternative source of the beads or develop an alternative process methodology to enable supply of our cell therapies. Should ThermoFisher change its process or make changes to its product, we may have to validate those changes to ensure there is no impact to our cell therapies. Such validation, including any comparability testing, will take additional time and resources.

We rely on third parties to manufacture and supply our cell therapies and to develop next generation cell therapies, and we may have to rely on third parties to produce and process our cell therapies, if approved.

We rely on a limited number of third-party manufacturers and third party service providers for clinical trial product supplies and services at each stage of the manufacturing process, and as a result we are exposed to the following risks (including where such third party risks arise as a result of the impact of COVID-19):

60

Table of Contents

61

Table of Contents

Certain of the components required for manufacturing of our cell therapies come from sole source or limited source suppliers.

Certain raw materials or precursor materials used in the manufacture and supply of our cell therapies may come from sole source or limited source suppliers. For example, there are currently a limited number of third party manufacturers within the U.S. that can supply us with our lentiviral delivery vector and ThermoFisher is currently the only supplier of the Dynabeads® CD3/CD28 technology. Should such suppliers be unable to supply or manufacture such raw materials or precursor materials either at all or within required timescales we may be unable to supply our cell therapies or such supply may be significantly delayed. Inability to obtain such raw materials or precursor materials may also necessitate changes in the manufacturing process used for supply of our cell therapies. Such changes to the manufacturing process may need to be developed internally or by a third party and may also require additional regulatory approvals to be obtained before they can be used for the manufacture and supply of our cell therapies for clinical trials.

In addition, we are focusing manufacture of our cell therapies at a single manufacturing site, namely our Navy Yard facility for autologous cell therapies and our new UK facility for allogeneic cell therapies. Should either facility be unable to manufacture our cell therapies for any reason, including natural disaster, contamination or for any regulatory reason, we may be unable to supply cell therapies for our clinical trials unless we can procure manufacture from a third party manufacturer. There is no assurance that we will be able to procure manufacture from a third party manufacturer or that such manufacture will be provided within the timescales we require or at an acceptable price. Any change in manufacturer used to produce our cell therapies requires notification to regulatory authorities which can be time consuming. There is no assurance that regulatory authorities will agree that any change in manufacturer is acceptable or that the processes used at such manufacturer are comparable to the processes previously used and additional evidence of comparability may be required.

We rely on third parties to conduct our clinical trials.

We depend upon independent investigators and collaborators, such as universities, medical institutions, CROs and strategic partners to conduct our preclinical programs and sponsored clinical trials under agreements with us. We expect to have to negotiate budgets and contracts with CROs and trial sites (either directly or through a third party consultant), which may result in delays to our development timelines and increased costs. We rely heavily on these third parties over the course of our clinical trials, and we do not have day-to-day control of their activities. Nevertheless, we are responsible for ensuring that each of our trials is conducted in accordance with applicable protocols and legal, regulatory and scientific standards, and our reliance on third parties does not relieve us of our regulatory responsibilities.

We and these third parties are required to comply with cGCPs, which are regulations and guidelines enforced by the FDA and comparable foreign regulatory authorities for cell therapies in clinical development. Regulatory authorities enforce these cGCPs through periodic inspections of trial sponsors, principal investigators and trial sites. If we or any of these third parties fail to comply with applicable cGCP regulations and guidelines (including as a result of the outbreak of COVID-19), the clinical data generated in our clinical trials may be deemed unreliable and the FDA or comparable foreign regulatory authorities may require us to perform additional clinical trials before approving our marketing authorization applications. Moreover, our business may be implicated if any of these third parties violates federal or state fraud and abuse or false claims laws and regulations or healthcare privacy and security laws.

Any third parties conducting our clinical trials are not and will not be our employees and, except for remedies available to us under our agreements with such third parties which could be limited, we cannot control whether or not they devote sufficient time and resources to our ongoing clinical trials and preclinical programs. These third parties may also have relationships with other commercial entities, including our competitors, for whom they may also be conducting clinical trials or other drug or biologic development activities, which could affect their performance on our behalf. If these third parties do not successfully carry out their contractual duties or obligations or meet expected deadlines

62

Table of Contents

(including as a result of the outbreak of COVID-19), if they need to be replaced or if the quality or accuracy of the clinical data they obtain is compromised due to the failure to adhere to our clinical protocols or regulatory requirements or for other reasons, our clinical trials may be extended, delayed or terminated and we may not be able to complete development of, obtain regulatory approval of, or successfully commercialize our cell therapies. As a result, our financial results and the commercial prospects for our cell therapies would be harmed, our costs could increase and our ability to generate revenue could be delayed.

Switching or adding third parties to conduct our clinical trials involves substantial cost and requires extensive management time and focus. In addition, there is a natural transition period when a new third party commences work. As a result, delays may occur, which can materially impact our ability to meet our timelines for bringing our cell therapies to market, if at all.

Risks Related to Our Intellectual Property

We may be forced to litigate to enforce or defend our intellectual property rights, and/or the intellectual property rights of our licensors.

We may be forced to litigate to enforce or defend our intellectual property rights against infringement and unauthorized use by competitors, and to protect our trade secrets. In so doing, we may place our intellectual property at risk of being invalidated, held unenforceable, narrowed in scope or otherwise limited. Further, an adverse result in any litigation or defense proceedings may increase the risk of non-issuance of pending applications. In addition, if any licensor fails to enforce or defend its intellectual property rights, this may adversely affect our ability to develop and commercialize our SPEAR T-cells and to prevent competitors from making, using, and selling competing products. Any such litigation could be very costly and could distract our management from focusing on operating our business. The existence and/or outcome of any such litigation could harm our business, results of operations and financial condition.

Furthermore, because of the substantial amount of discovery required in connection with intellectual property litigation, there is a risk that some of our confidential and proprietary information could be compromised by disclosure during this type of litigation. In addition, there could be public announcements of the results of hearings, motions or other interim proceedings or developments. If securities analysts or investors perceive these results to be negative, it could have a substantial adverse effect on the price of our ADSs.

We may also be forced to defend our intellectual property rights in opposition proceedings in front of patent offices in order to obtain or continue to hold granted patent rights. Our inability to successfully defend our patents and patent applications in opposition proceedings may result in a reduction in the scope of protection offered by such patents or patent applications or alternatively the patents or patent applications may be revoked. Anonymous third party oppositions have been lodged against certain our European patents. None of these oppositions relate to any cases which claim any of our clinical candidates.

​

We may not be able to protect our proprietary technology in the marketplace or the cost of doing so may be prohibitive or excessive.

Our success will depend, in part, on our ability to obtain patents, protect our trade secrets and operate without infringing on the proprietary rights of others. We rely upon a combination of patents, trade secret protection (i.e., know-how), and confidentiality agreements to protect the intellectual property of our cell therapies. However, patent protection may not be available for some of the cell therapies or technology we are developing. If we must spend significant time and money protecting or enforcing our patents, designing around patents held by others or licensing, potentially for large fees, patents or other proprietary rights held by others, our business results of operations and financial condition may be harmed.

Proceedings to enforce our patent rights in foreign jurisdictions could result in substantial cost and divert our efforts and attention from other aspects of our business. Enforcement of patents may also be cost prohibitive and we may be unable to prevent competitors from entering the market with products that are similar to or the same as our cell therapies.

63

Table of Contents

In addition, patents have a limited lifespan. In most countries, including the U.S., the standard expiration of a patent is 20 years from the effective filing date. Various extensions of patent term may be available in particular countries; however, in all circumstances the life of a patent, and the protection it affords, has a limited term. If patent term extension is not available, our competitors may be able to take advantage of our investment in development and clinical trials by referencing our clinical and non-clinical data, and then may be able to launch their product earlier than might otherwise be the case.

We may be unable to adequately prevent disclosure of trade secrets and other proprietary information.

We rely on trade secrets to protect our proprietary know-how and technological advances, especially where we do not believe patent protection is appropriate or obtainable. However, trade secrets are difficult to protect. We rely, in part, on confidentiality agreements with our employees, consultants, outside scientific collaborators, sponsored researchers and other advisors to protect our trade secrets and other proprietary information. These agreements may not effectively prevent disclosure of confidential information and may not provide an adequate remedy in the event of unauthorized disclosure of confidential information. Proceedings to enforce trade secrets can be cost prohibitive and we may be unable to prevent our competitors using our trade secrets.

If third parties claim that our activities or products infringe upon their intellectual property, our operations could be adversely affected.

There is a substantial amount of litigation, both within and outside the U.S., involving patents and other intellectual property rights in the pharmaceutical industry. If we or our third party suppliers were found to infringe upon a patent or other intellectual property right, or if we failed to obtain or renew a license under a patent or other intellectual property right from a third party, or if a third party that we were licensing technologies from was found to infringe upon a patent or other intellectual property rights of another third party, we may be required to pay damages, including triple damages if the infringement is found to be willful, suspend the manufacture of certain of our cell therapies or reengineer or rebrand our cell therapies, if feasible, or we may be unable to enter certain new product markets. Any such claims could also be expensive and time- consuming to defend and divert management’s attention and resources.

Licenses may be required from third parties in relation to any of cell therapies developed or commercialized by us.

We may identify third-party intellectual property rights that are required to enable the further development, commercialization, manufacture or development of our SPEAR T-cells or other cell therapies, including our allogeneic cell therapies. Licenses to such intellectual property rights may or may not be available on commercial terms that are acceptable to us. As a result we may incur additional license fees for such intellectual property rights, or the cost and expenses to identify an alternative route for commercialization, that does not require the relevant third-party intellectual property rights, or the cost and diversion of resources required to challenge any such third party intellectual property rights.

Where we license certain technology from a third party, the prosecution, maintenance and defense of the patent rights licensed from such third party may be controlled by the third party which may impact the scope of patent protection which will be obtained or enforced.

Where we license patent rights or technology from a third-party, control of such third party patent rights may vest in the licensor, particularly where the license is non-exclusive or field restricted. This may mean that we are not able to control or affect the scope of the claims of any relevant third-party patent or have control over any enforcement of such a patent. Where a licensor brings an enforcement action, this could negatively impact our business or result in additional restrictions being imposed on the license we have and the scope of such license or result in invalidation or limitation of the scope of the licensed patent. In addition, should we wish to enforce the relevant patent rights against a third person, we may be reliant on consent from the relevant licensor or the cooperation of the licensor. The licensor may refuse to bring such action and leave us unable to restrict competitor entry into the market.

64

Table of Contents

Issued patents protecting our SPEAR T-cells or other cell therapies could be found invalid or unenforceable if challenged in court or at the USPTO.

If we or one of our collaborators initiate legal proceedings against a third party to enforce a patent protecting one of our SPEAR T-cells or cell therapies, the defendant could counterclaim that the patent protecting our cell therapy, as applicable, is invalid and/or unenforceable. In patent litigation in the U.S., defendant counterclaims alleging invalidity and/or unenforceability are commonplace, and there are numerous grounds upon which a third party can assert invalidity or unenforceability of a patent. Third parties may also raise similar claims before administrative bodies in the United States or abroad, even outside the context of litigation. Such mechanisms include re-examination, post grant review, and equivalent proceedings in foreign jurisdictions (e.g., opposition proceedings). Such proceedings could result in revocation or amendment to our patents in such a way that they no longer cover our cell therapies.

General Business Risks

We depend upon our key personnel and our ability to attract and retain employees.

We are heavily dependent on the ongoing employment and involvement of certain key employees in particular, Adrian Rawcliffe, our Chief Executive Officer; Dr. Helen Tayton-Martin, our Chief Business and Strategy Officer; William Bertrand, our Chief Operating Officer; John Lunger, our Chief Patient Supply Officer; Dr. Joanna Brewer, our Chief Scientific Officer; Dr. Elliot Norry, our Chief Medical Officer; and Gavin Wood, our Chief Financial Officer. We do not hold key-man insurance for our senior managers.

Our business is dependent on our ability to recruit experienced and suitably trained employees or consultants, and to retain such employees on a long-term basis. Despite our efforts to retain valuable employees, members of our management, scientific and development teams may terminate their employment with us on short notice which could result in us being unable to conduct our business in accordance with current timelines and priorities. Although we have employment agreements with all of our employees in the U.K., these employment agreements provide for a mutual nine months’ notice period in the case of Dr. Tayton-Martin, Mr. Wood and Dr. Brewer; mutual three months’ or two months’ notice periods in the case of senior managers and mutual one-month notice periods for all other employees. In the U.S., the employment agreements provide for at-will employment except that, under their employment agreements, Mr. Rawcliffe, Mr. Bertrand, Mr. Lunger and Dr. Norry must provide 60 days’ written notice and our senior vice-presidents must provide 30 days’ written notice. This means that any of our employees in the U.S., except for Mr. Rawcliffe, Mr. Bertrand, Mr. Lunger, Dr. Norry and our senior vice-presidents, could leave our employment at any time, with or without notice. In November 2022, we announced a headcount reduction and de-prioritization of non-core programs to extend our cash runway. Any headcount reduction may impact our ability to retain other experienced members of staff which could in turn impact our ability to progress our development programs on the timelines currently expected.

We will need to grow the size and capabilities of our organization, and we may experience difficulties in managing this growth.

As of December 31, 2022, we had 534 employees. As our development and commercialization plans and strategies develop, we will need to add a significant number of additional managerial, operational, sales, marketing, financial, and other personnel. Future growth will impose significant added responsibilities on members of management, including:

65

Table of Contents

Our management may also have to divert a disproportionate amount of its attention away from day-to-day activities in order to devote a substantial amount of time to managing growth activities and the resourcing of replacement employees in the event employees leave. The ability to hire additional individuals and to integrate those individuals into the business may be more difficult whilst the COVID-19 pandemic is ongoing given the need for certain employees to work from home, the difficulty in providing adequate training and the inability to conduct interviews in person. In November 2022, we announced a headcount reduction and de-prioritization of non-core programs to extend our cash runway. The impact of the ongoing business and employees as a result of any headcount reduction is difficult to predict and will require management to divert attention away from day-to-day activities in order to manage the reduction in headcount and transition of activities to remaining individuals.

We expect to face intense competition, which may be from companies with greater resources and experience than we have.

The pharmaceutical industry, and the immuno-oncology industry specifically, is highly competitive and subject to rapid developments in treatment options. Competitors include large global pharmaceutical companies, biotechnology companies, specialty immune-therapy companies and universities and research organizations, whether alone or in collaboration with other entities. Many of our competitors have substantially greater financial, technical and other resources, such as larger research and development staff and may also be able to progress clinical candidates through clinical studies quicker than we are able to. Mergers and acquisitions within the pharmaceutical and biotechnology industry can also result in resources being concentrated within our competitors. Our competitors may also have better developed commercialization capabilities and already established sales forces and manufacturing capability.

Within in any particular cancer indication we may face competition from other cell therapy companies, from personalized medicine approaches, from other modalities of treatment, alternative drug products or therapies or from pre-existing treatment regimens used to treat patients with that cancer indication.

66

Table of Contents

Our internal information technology systems, or those of our partners, third-party CROs or other contractors or consultants, may fail or suffer cybersecurity incidents, including related to data protection and privacy laws and adversely affect our business and operations.

In the ordinary course of business, we collect, store, use, transmit, disclose and otherwise process proprietary, confidential and sensitive data (including personal data such as health-related data), intellectual property and trade secrets. We may process such information on our internal networks or rely upon third-party service providers, partners, CROs and other contractor and consultants, and technologies, to operate critical business systems to process such information in a variety of contexts (including, without limitation, third-party providers of cloud-based infrastructure, personnel email and other functions). Despite the implementation of security policies and procedures, the computer systems on which such information is processed or stored may be subject to cybersecurity threats. Our third-party providers may also be subject to cybersecurity threats which they do not detect on a timely basis and which may in turn impact our business. During the fourth quarter of 2022 one of our third party suppliers suffered a cybersecurity breach which resulted in payments being made to the wrong accounts. There was no financial impact to the Company as a result of the breach. We have implemented additional verification steps to mitigate the risk of a similar breach to third party systems that could affect us in the future.

We may not be able to anticipate all types of security threats, and we may not be able to implement preventive measures effective against all such security threats. If a failure, accidental or cybersecurity breach were to occur and cause interruptions, it could result in a breach, loss or compromise of critical or sensitive information, including personal information, and could give rise to legal liability and regulatory action under data protection and privacy laws such as the General Data Protection Regulation (“GDPR”) and relevant member state law in the European Union, the California Consumer Privacy Act and the California Privacy Rights Act (“CCPA”), and other domestic state and federal privacy laws that have been or may be passed such as HIPAA, and such laws may result in liability through private actions and enforcement or could greatly increase our cost of providing our products and services or even prevent us from offering certain services in jurisdictions in which we operate. Moreover, because we maintain sensitive company data on our computer networks, including our intellectual property and proprietary business information, any such security breach may compromise information stored on our networks and may result in significant data losses or theft of our intellectual property or proprietary business information. Our current cybersecurity liability insurance, and any such insurance that we may obtain in the future, may not cover the damages we would sustain based on any breach of our computer security protocols or other cybersecurity attack. To the extent that any disruption or security breach results in a loss of or damage to our data or applications or other data or applications relating to our technology or product candidates, or inappropriate disclosure of confidential or proprietary information, our reputation could be harmed and we could incur significant liabilities and the further development, clinical evaluation, or commercialization of our product candidates could be disrupted.

We are exposed to risks related to currency exchange rates.

We conduct a significant portion of our operations within the U.K.in both U.S. dollars and pounds sterling and our arrangements with GSK are denominated in pounds sterling. Changes in currency exchange rates have had and could have a significant effect on our operating results. Exchange rate fluctuations between the U.S. dollar and local currencies create risk in several ways, including the following: weakening of the pound sterling may increase the cost of overseas research and development expenses and other costs outside the U.K.; strengthening of the U.S. dollar may decrease the value of any future revenues denominated in other currencies. Effects of exchange rates on transactions and cash deposits held in a currency other than the functional currency of a subsidiary can distort our financial results; and commercial pricing and profit margins are affected by currency fluctuations.

Risks Related to Ownership of our American Depositary Shares (ADSs)

The market price and trading volume of our ADSs may be volatile.

Many factors may have a material adverse effect on the market price of the ADSs, including but not limited to:

67

Table of Contents

68

Table of Contents

In addition, the stock market in general, and Nasdaq and biopharmaceutical companies in particular, have experienced extreme price and volume fluctuations that have often been unrelated or disproportionate to the operating performance of these companies. Broad market and industry factors may negatively affect the market price of our ADSs, regardless of our actual operating performance. Further, a decline in the financial markets and related factors beyond our control may cause the price of our ADSs to decline rapidly and unexpectedly. In the past, securities class action litigation has often been instituted against companies following periods of volatility in their stock price. This type of litigation could result in substantial costs and could divert our management and other resources.

Substantial future sales of our ADSs in the public market, or the perception that these sales could occur, could cause the price of the ADSs to decline and dilute shareholders.

Substantial future sales of our ADSs in the public market, or the perception that these sales could occur, could cause the market price of the ADSs to decline. Sales of a substantial number of our ADSs in the public market could occur at any time. In addition, we have registered an aggregate of 151,248,915 ordinary shares that we may issue under our equity compensation plans and, as a result, they can be freely sold in the public market upon issuance and following conversion into ADSs, but subject to volume limitations applicable to affiliates under Rule 144. Additionally, the majority of ordinary shares that may be issued under our equity compensation plans also remain subject to vesting in tranches over a four-year period. As of December 31, 2022, an aggregate of 75,064,373 options over our ordinary shares had vested and become exercisable. If a large number of our ADSs are sold in the public market after they become eligible for sale, the sales could reduce the trading price of our ADSs and impede our ability to raise capital in the future.

We incur increased costs as a result of being a public company whose ADSs are publicly traded in the U.S. and our management must devote substantial time to public company compliance and other compliance requirements.

As a U.S. public company whose ADSs trade on Nasdaq, we have incurred and will continue to incur significant legal, accounting, insurance and other expenses. We are subject to the reporting requirements of the Exchange Act, which requires, among other things, that we file with the SEC annual, quarterly and current reports with respect to our business and financial condition and must comply with the Nasdaq listing requirements and other applicable securities rules and regulations. In addition, the Sarbanes-Oxley Act, as well as rules subsequently adopted by the SEC and the Nasdaq to implement provisions of the Sarbanes-Oxley Act, impose significant requirements on public companies, including requiring establishment and maintenance of effective disclosure and financial controls and changes in corporate governance practices.

We expect the rules and regulations applicable to public companies to substantially increase our legal and financial compliance costs and to make some activities more time-consuming and costly. Our insurance costs have increased, particularly for directors and officers liability insurance, and we may be required to incur further substantial increased costs to maintain the same or similar coverage or be forced to accept reduced coverage in future. To the extent these requirements divert the attention of our management and personnel from other business concerns, they could have a material adverse effect on our business, financial condition and results of operations. The increased costs will increase our net loss and may require us to reduce costs in other areas of our business or increase the requirement for future financing. These laws and regulations could also make it more difficult and expensive for us to attract and retain qualified persons to serve on our board of directors, our board committees or as our executive officers. Furthermore, if we are unable to satisfy our obligations as a public company, we could be subject to delisting of the ADSs from Nasdaq, fines, sanctions and other regulatory action and potentially civil litigation.

Raising additional capital may cause dilution to our existing shareholders, restrict our operations or require us to relinquish rights to our technologies or product candidate.

We may seek additional capital through a combination of public and private equity offerings, debt financings, strategic partnerships and alliances and licensing arrangements. To the extent that we raise additional capital through the sale of equity or convertible debt securities, your ownership interest will be diluted, and the terms may include liquidation or other preferences that adversely affect your rights as a shareholder. The incurrence of indebtedness would result in increased fixed payment obligations and could involve certain restrictive covenants, such as limitations on our ability to incur additional debt, limitations on our ability to acquire or license intellectual property rights and other

69

Table of Contents

operating restrictions that could adversely impact our ability to conduct our business. If we raise additional funds through strategic partnerships and alliances and licensing arrangements with third parties, we may have to relinquish valuable rights to our technologies or product candidates, or grant licenses on terms unfavorable to us.

We may be classified as a passive foreign investment company in any taxable year and U.S. holders of our ADSs could be subject to adverse U.S. federal income tax consequences.

The rules governing passive foreign investment companies, or PFICs, can have adverse effects for U.S. federal income tax purposes. The tests for determining PFIC status for a taxable year depend upon the relative values of certain categories of assets and the relative amounts of certain kinds of income. The determination of whether we are a PFIC depends on the particular facts and circumstances (such as the valuation of our assets, including goodwill and other intangible assets) and may also be affected by the application of the PFIC rules, which are subject to differing interpretations. In addition, it is not entirely clear how to apply the income test to a company like us, which for any particular taxable year may have gross income that is either entirely passive or that significantly exceeds any active gross income, but the overall losses of which from research and development activities exceed the overall amount of its gross income for that year. Based on our estimated gross income, the average value of our assets, including goodwill and the nature of our active business, although not free from doubt, we do not believe that the Company was classified as a PFIC for U.S. federal income tax purposes for the U.S. taxable year ended December 31, 2022. There can be no assurance, however, that we will not be considered to be a PFIC for this taxable year or any particular year in the future because PFIC status is factual in nature, depends upon factors not wholly within our control, generally cannot be determined until the close of the taxable year in question and is determined annually.

If we are a PFIC, U.S. holders of our ADSs would be subject to adverse U.S. federal income tax consequences, such as ineligibility for any preferred tax rates on capital gains or on actual or deemed dividends, interest charges on certain taxes treated as deferred, and additional reporting requirements under U.S. federal income tax laws and regulations. A U.S. holder of our ADSs may be able to mitigate some of the adverse U.S. federal income tax consequences described above with respect to owning the ADSs if we are classified as a PFIC, provided that such U.S. investor is eligible to make, and validly makes, a “mark-to-market” election. In certain circumstances a U.S. Holder can make a “qualified electing fund” election to mitigate some of the adverse tax consequences described with respect to an ownership interest in a PFIC by including in income its share of the PFIC’s income on a current basis. However, we do not currently intend to prepare or provide the information that would enable a U.S. Holder to make a qualified electing fund election.

Investors should consult their own tax advisors regarding our PFIC status for any taxable year and the potential application of the PFIC rules to an investment in our ADSs or ordinary shares.

If we fail to establish and maintain proper internal controls, our ability to produce accurate financial statements or comply with applicable regulations could be impaired. A material weakness related to our risk assessment process over the design, implementation and operational effectiveness of controls over deferred income taxes, specifically the accounting for deferred income tax asset valuation allowance, was identified as part of the audit of our financial statements for the fiscal year ended December 31, 2021, the remediation of which will require significant costs and resources.

We must maintain effective internal control over financial reporting in order to accurately and timely report our results of operations and financial condition. The rules governing the standards that must be met for our management to assess our internal control over financial reporting pursuant to Section 404 of the Sarbanes-Oxley Act are complex and require significant documentation, testing and possible remediation. These stringent standards require that our audit committee be advised and regularly updated on management’s review of internal control over financial reporting.

Our compliance with applicable provisions of Section 404 requires that we incur substantial accounting expenses and expend significant management attention and time on compliance-related issues as we implement additional corporate governance practices and comply with reporting requirements. If we fail to staff our accounting and finance function adequately, if key employees within our accounting and finance function leave, or if we fail to maintain internal control over financial reporting adequate to meet the requirements of the Sarbanes-Oxley Act, our business and reputation may be harmed. Moreover, if we are not able to comply with the applicable requirements of Section 404 in a timely manner, we may be subject to sanctions or investigations by regulatory authorities, including the SEC and

70

Table of Contents

Nasdaq. Furthermore, if we are unable to conclude that our internal control over financial reporting is effective or if our independent registered public accounting firm identifies deficiencies in our internal control over financial reporting that are deemed to be material weaknesses, we could lose investor confidence in the accuracy and completeness of our financial reports, the market price of our ADSs could decline, and we could be subject to sanctions or investigations by the SEC, Nasdaq or other regulatory authorities. Failure to implement or maintain effective internal control systems required of U.S. public companies could also restrict our access to the capital markets. The occurrence of any of the foregoing would also require additional financial and management resources.

In connection with the audit of our financial statements for the fiscal year ended December 31, 2021, we identified a material weakness. This was related to our risk assessment process over the design, implementation and operational effectiveness of controls over deferred income taxes, specifically the accounting for deferred income tax asset valuation allowance. This material weakness resulted in a material misstatement in deferred income taxes that was corrected prior to the issuance of the financial statements. A material weakness is a deficiency, or a combination of deficiencies, in internal control over financial reporting, such that there is a reasonable possibility that a material misstatement of our annual or interim financial statements will not be prevented or detected on a timely basis. The underlying causes of this material weakness have been identified and primarily relate to insufficient experience and inadequate training for new individuals to identify and address the relevant risks and design of and to implement and operate controls over the related process and risks.

​

We have taken steps to remediate the material weakness, including (i) recruiting appropriate personnel with appropriate qualification, including a Vice President Financial Controller with experience of income tax accounting; (ii) improving the design of our controls for deferred income taxes, specifically in enhancing the requirements to perform the assessment of deferred income tax assets to enable new personnel to effectively execute the control and (iii) enhancing the training provided to the individuals operating the deferred income taxation controls.

U.S. investors may have difficulty enforcing civil liabilities against our company, our directors, officers and members of senior management.

We are incorporated under the laws of England and Wales. The rights of holders of our ordinary shares and, therefore, certain of the rights of holders of ADSs, are governed by English law, including the provisions of the Companies Act 2006, and by our articles of association. These rights differ in certain respects from the rights of shareholders in typical U.S. corporations organized in, for example, Delaware. Some of our directors, officers and members of senior management reside outside the U.S., and a substantial portion of our assets and all or a substantial portion of the assets of such persons are located outside the U.S. As a result, it may be difficult for you to serve legal process on us or our directors and executive officers or have any of them appear in a U.S. court. The U.S. and the U.K. do not currently have a treaty providing for the recognition and enforcement of judgments, other than arbitration awards, in civil and commercial matters. The enforceability in the U.K. of any judgment of a U.S. federal or state court will depend on the particular facts of the case as well as the laws and any treaties in effect at the time, including conflicts of laws principles (such as those bearing on the question of whether a U.K. court would recognize the basis on which a U.S. court had purported to exercise jurisdiction over a defendant). In this context, there is doubt as to the enforceability in the U.K., in original actions or in actions for enforcement of judgments of U.S. courts, of civil liabilities based solely on the federal securities laws of the U.S.. In addition, awards for punitive damages in actions brought in the U.S. or elsewhere may be unenforceable in the U.K. An award for monetary damages under the U.S. securities laws would likely be considered punitive if it did not seek to compensate the claimant for loss or damage suffered and was intended to punish the defendant.

Provisions in the U.K. City Code on Takeovers and Mergers that may have anti-takeover effects do not apply to us.

The U.K. City Code on Takeovers and Mergers, or the Takeover Code, applies to an offer for, among other things, a public company whose registered office is in the U.K. if the company is considered by the Panel on Takeovers and Mergers, or the Takeover Panel, to have its place of central management and control in the United Kingdom (or the Channel Islands or the Isle of Man). This is known as the “residency test.” The test for central management and control under the Takeover Code is different from that used by the U.K. tax authorities. Under the Takeover Code, the Takeover Panel will determine whether we have our place of central management and control in the United Kingdom by looking at various factors, including the structure of our Board, the functions of the directors and where they are resident.

71

Table of Contents

In July 2018, the Takeover Panel confirmed that, based on our current circumstances, we are not subject to the Takeover Code. As a result, our shareholders are not entitled to the benefit of certain takeover offer protections provided under the Takeover Code. We believe that this position is unlikely to change at any time in the near future but, in accordance with good practice, we will review the situation on a regular basis and consult with the Takeover Panel if there is any change in our circumstances which may have a bearing on whether the Takeover Panel would determine our place of central management and control to be in the United Kingdom.

​

Item 1B. Unresolved Staff Comments

None.

Item 2.  Properties

The following table summarizes the facilities we lease as of December 31, 2022, including the location and size of the facilities, and their primary use.

​

As of December 31, 2022, all of the above sites were utilized by the Company. During January 2023, the Company served notice to terminate the lease of one of its facilities in Abingdon, Oxfordshire of 11,657 square feet effective on May 31, 2023.

We believe that our existing facilities are adequate for our near-term needs, but we expect to need additional space as we grow and expand our operations. We believe that suitable additional or alternative office, laboratory, and manufacturing space will be available as required in the future on commercially reasonable terms.

​

Item 3.  Legal Proceedings

As of December 31, 2022, we were not a party to any material legal proceedings.

Item 4.  Mine Safety Disclosures

Not applicable

72

Table of Contents

PART II

Item 5.  Market for Registrant’s Common Equity, Related Stockholder Matters and Issuer Purchases of Equity Securities

General Market Information

Our ADSs have been listed on The Nasdaq Global Select Market since May 6, 2015 and are traded under the symbol “ADAP”. Each ADS represents six ordinary shares. As of March 3, 2023, there were approximately 27 holders of record of our ordinary shares, par value £0.001 per share, and approximately nine holders of record of our ADSs. The closing sale price per ADS on Nasdaq on March 3, 2023 was $1.76.

Equity Compensation Plans

For information about our equity compensation plans, see Part III, Item 11, below

Sales of Unregistered Securities

We did not sell any unregistered securities during the year ended December 31, 2022.

Company Purchases of Equity Securities

We did not repurchase any of our equity securities during the year ended December 31, 2022.

Stock Performance Graph

Notwithstanding any statement to the contrary in any of our previous or future filings with the Securities and Exchange Commission, the following information relating to the price performance of our ADSs shall not be deemed “filed” with the Securities and Exchange Commission or “soliciting material” under the Exchange Act and shall not be incorporated by reference into any such filings.

The following graph compares the cumulative total shareholder return on our ADSs with that of the Nasdaq Biotech Index and the Nasdaq Composite Index for the period that our ADSs were publicly traded, which commenced

73

Table of Contents

on May 6, 2015. We selected the Nasdaq Biotech Index because our ADSs trade on The Nasdaq Global Select Market and we believe this indicates our relative performance against a group consisting of more similarly situated companies.

​

Item 6.   [Reserved]

​

Item 7.   Management’s Discussion and Analysis of Financial Condition and Results of Operations

You should read the following discussion and analysis of our financial condition and results of operations in conjunction with our consolidated financial statements and the related notes to those statements included elsewhere in this Annual Report. In addition to our historical consolidated financial information, the following discussion contains forward-looking statements that reflect our plans, estimates, beliefs and expectations. Our actual results and the timing of events could differ materially from those discussed in these forward-looking statements. Factors that could cause or contribute to these differences include those discussed below and elsewhere in this Annual Report, particularly in Part I, Item 1A. “Risk Factors.”

​

Overview

We are a clinical-stage biopharmaceutical company focused on providing novel cell therapies to people with cancer. We are a leader in the development of T-cell therapies for solid tumors and have reported responses in multiple solid tumor indications.

​

Our proprietary platform enables us to identify cancer targets, find and develop cell therapy candidates active against those targets and produce therapeutic candidates for administration to patients. Our cell therapy candidates include genetically engineered T-cell receptors (“TCRs”) and HLA-independent TCRs (“HiTs”) where surface proteins are targeted independently of the peptide-HLA complex. Our cell therapies are currently manufactured on an autologous or per patient basis and we have a proprietary preclinical allogeneic platform for the development of “off the shelf” cell therapies.

​

Our MAGE-A4 cell therapy franchise includes T-cell therapy products targeting solid tumor indications in which the MAGE-A4 antigen is expressed, with responses seen in eight indications (head and neck, esophagogastric junction (“EGJ”), non-small cell lung cancer (NSCLC)-squamous, synovial sarcoma, melanoma, urothelial, ovarian and myxoid/round cell liposarcoma (MRCLS) indications). Filing of a Biologics License Application (BLA) for the lead

74

Table of Contents

product (afamitresgene autoleucel or “afami-cel”) in synovial sarcoma has been initiated with the U.S. Food and Drug Administration (“FDA”), with completion of the filing targeted for mid-2023.

​

Clinical programs with our MAGE-A4 targeted cell therapies are focused around synovial sarcoma with afami-cel and urothelial, head and neck and ovarian cancers with our ADP-A2M4CD8 cell therapy:

​

​

​

​

Outside of the MAGE-A4 franchise, we have a preclinical program for T-cell therapies directed to the PRAME target which is expressed in a broad range of tumors. This program is being transitioned from GSK following termination of our collaboration agreement with GSK. Dependent on the data arising from the preclinical program, the first cell therapy targeting PRAME is anticipated to be IND-ready by the end of 2023.

​

We are also developing allogeneic or “off-the-shelf” cell therapies utilizing a proprietary allogeneic platform. The platform utilizes cells derived from Induced Pluripotent Stem Cells (“iPSCs”), which can be gene-edited to express our engineered TCRs or other constructs and then differentiated into the required end cell type, for example T-cells. The platform is applicable to all of our cell therapies.

We have a strategic collaboration with Genentech Inc (“Genentech”). The collaboration with Genentech covers the research and development of “off-the-shelf” cell therapies for up to five shared cancer targets (“off-the-shelf” products) and the development of a novel allogeneic personalized cell therapy platform.

We also have several development and research collaborations including a clinical and preclinical alliance agreement with MD Anderson Cancer Center. A prior collaboration with GSK terminated during 2022 and we are negotiating a transition agreement with GSK in relation to ongoing clinical trials with T-cell therapies directed to the NY-ESO and PRAME targets. A prior Co-development and Co-commercialization agreement (the “Astellas Collaboration Agreement”) with Universal Cells, Inc., a wholly-owned subsidiary of Astellas Pharma Inc. under which we collaborated with Universal Cells to research, develop, and commercialize certain cellular therapy products directed to certain targets was mutually agreed to terminate as of March 6, 2023. Termination does not impact the development of our allogeneic cell lines for our internal allogeneic programs or for our collaboration with Genentech Inc. The parties previously terminated an Amended and Restated Research Collaboration and License Agreement, dated January 13, 2020, effective February 26, 2023.

​

We are an integrated cell therapy company with our own manufacturing facility in the U.S. for autologous products and in the United Kingdom (“U.K.”) for allogeneic products together with a dedicated lentiviral vector

75

Table of Contents

manufacturing in the UK. This enables us to continue improving the patient experience associated with our cell therapies including the ability to rapidly introduce improvements to the manufacturing process and patient supply chain.

In November 2022 we took a decision to focus our clinical and preclinical programs on the MAGE-A4 and PRAME targets including the BLA submission for afami-cel. We have stopped the SURPASS-2 trial in GE cancers and the TIL-IL7 program. We have also paused any further investment in non-core activities including certain preclinical programs including the HiT program, additional target programs (other than the PRAME program) and alternative HLA programs. We also announced that investment in commercialization of afami-cel will be delayed given the BLA filing timelines. Given the de-prioritisation of non-core programs resulting from this decision, we are undertaking associated cost reduction activities including a reduction in headcount of approximately 25% which we currently estimate will extend our cash runway into early 2025. The headcount reduction has now concluded.

On March 6, 2023 we announced entry into a definitive agreement under which we will combine with TCR² Therapeutics Inc (“TCR²”) in an all-stock transaction to create a preeminent cell therapy company focused on treating solid tumors. The combination provides extensive advantages for clinical development and product delivery supported by complementary technology platforms. The lead clinical franchises for the combined company will utilize engineered T-cell therapies targeting MAGE-A4 and mesothelin. These targets are expressed on a broad range of solid tumors and are supported by early- and late-stage clinical data. The combined company also has a preclinical pipeline of additional target opportunities with development initially focused on PRAME and CD70. The merger agreement was unanimously approved by the boards of directors of both companies. Following the closing of the transaction, Adaptimmune shareholders will own approximately 75% of the combined company and TCR² stockholders will own approximately 25% of the combined company. The agreement contains customary representations, warranties and covenants given by us and TCR². The agreement also contains customary pre-closing covenants, including covenants by each of the parties relating to conduct of their respective business prior to the closing of the transaction. The transaction is expected to close in Q2 2023, subject to the receipt of approvals by Adaptimmune shareholders and TCR² stockholders and satisfaction or waiver of other customary closing conditions. Following the closing of the transaction we currently estimate that the cash runway of the combined company will extend into early 2026.

We have generated losses since our inception in 2008, during which time we have devoted substantially all of our resources to the research and development of our cell therapies. We expect to continue to incur losses for the foreseeable future and our net losses may fluctuate significantly from quarter to quarter. Our expenses may increase significantly depending on the progress of our clinical trials, requirements to conduct additional clinical trials (including as a result of the filing of a BLA), requirement for further manufacturing to support our development activities, investment in additional manufacturing capabilities, requirements to support collaborations or engagement with third parties and investment in resources and infrastructure to support the planned commercialization of our cell therapies. Further information can be founded in Item 1A. Risk Factors.

​

COVID-19 pandemic and Our Business

​

During the COVID-19 pandemic we have continued to focus on ensuring the safety of our work force whilst continuing the work we do to make our therapies available to people with cancer.

76

Table of Contents

The pandemic has created challenges for conducting clinical trials and we continue to work with our clinical sites to enroll and treat patients at the earliest possible time particularly given that many of our patients have late-stage cancer. Certain clinical sites have chosen to postpone treatment of patients or participation in trials whilst the pandemic is impacting resources at those sites. We have experienced challenges around our supply chain. Many of the materials and consumables we require for manufacture and supply of products and also for research are also required for manufacture of COVID-19 vaccines and as a result these were prioritized to meet vaccine supplies. In certain cases, for example, in accordance with the U.S. Defense Production Act, suppliers were required to prioritize vaccine supplies. This resulted in some delays in supply of materials and consumables we require for our business, however, we were able to mitigate against impacts associated with any supply delays by purchasing in advance where possible, prioritizing use of such supplies and sourcing alternative suppliers where necessary.

We have continued and will continue to adjust our working practices as the pandemic evolves to ensure we can continue to treat people with cancer as quickly and as effectively as possible whilst protecting the health of our colleagues.

Financial Operations Overview

Revenue

The Company had three revenue-generating contracts with customers in the years ended December 31, 2022 and 2021: a collaboration and license agreement with GSK, a collaboration agreement with Astellas and a strategic collaboration and license agreement with Genentech.

The Genentech Collaboration and License Agreement

On September 3, 2021, Adaptimmune Limited, a wholly owned subsidiary of Adaptimmune Therapeutics Plc, entered into a Strategic Collaboration and License Agreement with Genentech, Inc. (“Genentech”) and F. Hoffman-La Roche Ltd. The collaboration has two components:

​

The parties will collaborate to perform a research program, initially during an eight-year period (which may be extended for up to two additional two-year terms at Genentech’s election upon payment of an extension fee for each two-year term), to develop the cell therapies, following which Genentech will determine whether to further develop and commercialize such therapies. The Company began recognizing revenue for the performance obligations relating to the initial “off-the-shelf” collaboration targets and the personalized therapies in 2021, however this did not have a material impact on the consolidated financial statements.

The Company identified the following performance obligations under the agreement: (i) research services and rights granted under the licenses for each of the initial “off-the-shelf” collaboration targets, (ii) research services and rights granted under the licenses for the personalized therapies, (iii) material rights relating to the option to designate additional “off-the-shelf” collaboration targets and (iv) material rights relating to the two options to extend the research term. The revenue allocated to the initial “off-the-shelf” collaboration targets and the personalized therapies is recognized as development progresses. The revenue allocated to the material rights to designate additional ‘off-the-shelf’ collaboration targets is recognized from the point that the options are exercised and then as development progresses, in line with the initial “off-the-shelf” collaboration targets, or at the point in time that the rights expire. The revenue from the material rights to extend the research term is recognized from the point that the options are exercised and then over period of the extension, or at the point in time that the options expire.

The GlaxoSmithKline (“GSK”) Collaboration and License Agreement

The GSK Collaboration and License Agreement consisted of multiple performance obligations. GSK nominated its third target under the Collaboration and License Agreement in 2019, and the Company received $3.2 million

77

Table of Contents

following the nomination of the target and a further $4.2 million in June 2021 following achievement of a development milestone, which were being recognized as revenue as development progressed.

The collaboration was terminated in October 2022. A further amendment to the collaboration agreement was entered into on December 19, 2022 for the deletion of certain provisions relating to GSK’s post termination manufacturing and supply obligations and payment of £5 million ($6 million) by GSK to Adaptimmune. The revenue associated with this payment and the remaining deferred income relating to the third target of $0.4 million were recognized as revenue in the year-ended December 31, 2022.

The Astellas Collaboration Agreement

On January 13, 2020, the Company entered into a collaboration agreement with Universal Cells Inc. a wholly owned subsidiary of Astellas Pharma Inc, (“Astellas”). The Company received a $50.0 million non-refundable upfront payment in January 2020 after entering into the agreement. Under the agreement the parties will agree on up to three targets and will co-develop T-cell therapies directed to those targets pursuant to an agreed research plan. For each target, Astellas will fund co-development up until completion of a Phase 1 trial for products directed to such target. In addition, Astellas was also granted the right to develop, independently of Adaptimmune, allogeneic T-cell therapy candidates directed to two targets selected by Astellas. Astellas will have sole rights to develop and commercialize products resulting from these two targets.

The agreement consists of the following performance obligations: (i) research services and rights granted under the co-exclusive license for each of the three co-development targets and (ii) the rights granted for each of the two independent Astellas targets. The revenue allocated to the co-development targets is recognized as the development of products directed to the targets progresses up until completion of a Phase 1 trial. The revenue allocated to each of the research licenses for the targets being independently developed by Astellas will be recognized when the associated license commences, which is upon designation of a target by Astellas. The agreement was terminated by mutual agreement on March 6, 2023.

Research and Development Expenses

Research and development expenditures are expensed as incurred. Research and development expenses consist principally of the following:

​

78

Table of Contents