lyel-20251231

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UNITED STATES

SECURITIES AND EXCHANGE COMMISSION

Washington, D.C. 20549

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FORM 10-K

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(Mark One)

For the fiscal year ended December 31, 2025

For the transition period from to

Commission file number 001-40502

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Lyell Immunopharma, Inc.

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(Exact name of registrant as specified in its charter)

South San Francisco, California 94080

(Address of Principal Executive Offices) (Zip Code)

(650) 695-0677

Registrant’s telephone number, including area code

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

Title of each class Trading Symbol(s) Name of each exchange on which registered

Common Stock, $0.0001 par value per share LYEL The Nasdaq Global Select Market

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 oNox

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 oNox

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. Yesx No o

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 such files). Yesx No o

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.

Large accelerated filer o Accelerated filer o

Non-accelerated filer x Smaller reporting company x

Emerging growth company o

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. o

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. o

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. o

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). o

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

The aggregate market value of the common stock held by non-affiliates of the registrant on June 30, 2025, the last business day of the registrant’s most recently completed second fiscal quarter, was approximately $129 million based on the closing price reported for such date on The Nasdaq Global Select Market.

The registrant had 23,307,143 shares of common stock outstanding as of March 9, 2026.

DOCUMENTS INCORPORATED BY REFERENCE

Portions of the registrant’s Proxy Statement for the 2026 Annual Meeting of Stockholders are incorporated herein by reference in Part III of this Annual Report on Form 10-K to the extent stated herein. Such proxy statement will be filed with the Securities and Exchange Commission within 120 days of the registrant’s fiscal year ended December 31, 2025.

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Lyell Immunopharma, Inc.

2025 Annual Report on Form 10-K

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Page

Special Note Regarding Forward-Looking Statements 1

Summary of Risk Factors 2

PART I

Item 1. Business 5

Item 1A. Risk Factors 35

Item 1B. Unresolved Staff Comments 78

Item 1C. Cybersecurity 78

Item 2. Properties 79

Item 3. Legal Proceedings 79

Item 4. Mine Safety Disclosures 80

PART II

Item 6. [Reserved] 81

Item 7A. Quantitative and Qualitative Disclosures About Market Risk 93

Item 8. Financial Statements and Supplementary Data 94

Item 9A. Controls and Procedures 127

Item 9B. Other Information 128

Item 9C. Disclosure Regarding Foreign Jurisdictions that Prevent Inspections 128

PART III

Item 10. Directors, Executive Officers and Corporate Governance 129

Item 11. Executive Compensation 129

Item 14. Principal Accountant Fees and Services 129

PART IV

Item 15. Exhibits and Financial Statement Schedules 130

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SPECIAL NOTE REGARDING FORWARD-LOOKING STATEMENTS

This Annual Report on Form 10-K contains forward-looking statements. All statements other than statements of historical facts contained in this Annual Report on Form 10-K, including statements regarding our future results of operations and financial position, business strategy, product candidates, planned nonclinical studies and clinical trials, results of nonclinical studies and clinical trials, research and development costs, planned regulatory submissions, regulatory approvals and the timing and likelihood of success, as well as plans and objectives of management for future operations, are forward-looking statements. These statements involve known and unknown risks, uncertainties and other important factors that are in some cases beyond our control and may cause our actual results, performance or achievements to be materially different from any future results, performance or achievements expressed or implied by the forward-looking statements.

In some cases, you can identify forward-looking statements by terms such as “may,” “will,” “should,” “would,” “expect,” “plan,” “anticipate,” “could,” “intend,” “target,” “project,” “believe,” “estimate,” “predict,” “potential” or “continue,” or the negative of these terms or other similar expressions. Forward-looking statements contained in this Annual Report on Form 10-K include, but are not limited to, statements about:

•the sufficiency of our existing cash to fund our future operating expenses and capital expenditure requirements;

•the accuracy and timing of our estimates regarding expenses, revenue opportunities, capital requirements and needs for additional financing;

•the scope, progress, results and costs of developing rondecabtagene autoleucel (ronde-cel, also known as LYL314), LYL273 (formerly known as GCC19CART) or any other product candidates we may develop or acquire, including both nonclinical studies and clinical trials;

•the timing and costs involved in obtaining and maintaining regulatory approvals of ronde-cel, LYL273 or any other product candidates we may develop or acquire, and the timing or likelihood of regulatory filings and approvals, including any expectations or plans regarding seeking or maintaining special designations, such as Regenerative Medicine Advanced Therapy designation, Orphan Drug designation or Fast Track designation, for our product candidates for various diseases;

•our plans relating to the commercialization of ronde-cel, LYL273 or any other product candidates we may develop or acquire, if approved, including the geographic areas of focus, and our ability to commercially differentiate such product candidates and build a sales force;

•the size of the market opportunities for ronde-cel, LYL273 or any other product candidates we may develop or acquire in each of the diseases we may target;

•our reliance on third parties to conduct research activities for ronde-cel, LYL273 or any other product candidates we may develop or acquire;

•the characteristics, safety, efficacy and therapeutic effects of ronde-cel, LYL273 or any other product candidates we may develop or acquire;

•the advancement of our technologies and the effectiveness and expected benefits of any of our technologies and manufacturing processes;

•our estimates of the number of patients in the United States and worldwide who suffer from the diseases we target and the number of patients that may enroll in our clinical trials;

•the progress and focus of the current and planned clinical trials of our product candidates, and the reporting of data from those trials, including the timing thereof;

•the ability of our clinical trials to sufficiently demonstrate the safety and efficacy of ronde-cel, LYL273 or any other product candidates we may develop or acquire, and other clinical trial results;

•the success of competing therapies that are, or may become, available;

•developments relating to our competitors and our industry, including any existing or future competing product candidates or therapies;

•our plans relating to the further development and manufacturing of ronde-cel, LYL273 or any other product candidates we may develop or acquire, including lines of therapy or additional indications that we may pursue;

•existing regulations and regulatory developments in the United States and other jurisdictions;

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•our potential and ability to successfully manufacture and supply or our ability to contract with third parties to manufacture and supply ronde-cel, LYL273 or any other product candidates we may develop or acquire for clinical trials and for commercial use, if approved;

•the rate and degree of market acceptance, as well as the pricing and reimbursement, of ronde-cel, LYL273 or any other product candidates we may develop or acquire, if approved;

•our continued reliance on third parties to assist us in conducting additional clinical trials of ronde-cel, LYL273 or any other product candidates we may develop or acquire;

•the scope of protection we are able to establish and maintain for intellectual property rights, including covering ronde-cel, LYL273 and other product candidates and technologies we may develop or acquire;

•our ability to retain the continued service of our key personnel and to identify, hire and retain additional qualified personnel;

•our expectations regarding the impact of inflation, macroeconomic conditions and geopolitical conflicts on our business and operations, including on our manufacturing suppliers, collaborators, contract research organizations (CROs) and employees;

•our ability to realize the anticipated benefits of and potential value created by our acquisition of ImmPACT Bio USA Inc. (ImmPACT), our acquisition of rights to LYL273 from Innovative Cellular Therapeutics or any other acquisition or strategic transaction and our success in commercializing any product candidates we acquire in connection therewith;

•our expectation that our LyFE Manufacturing CenterTM and, if applicable, contract drug manufacturing organizations engaged by us, will provide sufficient drug supply for our ongoing and planned clinical trials and through potential commercial launch; and

•our anticipated use of our existing cash, cash equivalents and marketable securities.

We have based these forward-looking statements largely on our current expectations and projections about our business, the industry in which we operate and financial trends that we believe may affect our business, financial condition, results of operations and prospects, and these forward-looking statements are not guarantees of future performance or development. These forward-looking statements speak only as of the date of this Annual Report on Form 10-K and are subject to a number of risks, uncertainties and assumptions described under “Risk Factors” in Part I, Item 1A, and elsewhere in this Annual Report on Form 10-K. Because forward-looking statements are inherently subject to risks and uncertainties, some of which cannot be predicted or quantified, you should not rely on these forward-looking statements as predictions of future events. The events and circumstances reflected in our forward-looking statements may not be achieved or occur, and actual results could differ materially from those projected in these forward-looking statements. Except as required by applicable law, we undertake no obligation to update or supplement any forward-looking statements publicly, or to update or supplement the reasons that actual results could differ materially from those projected in these forward-looking statements, even if new information becomes available in the future.

In addition, statements indicating that “we believe” and similar statements reflect our beliefs and opinions on the relevant subject. These statements are based upon information available to us as of the date of this Annual Report on Form 10-K, and while we believe such information forms a reasonable basis for such statements, such information may be limited or incomplete, and our statements should not be read to indicate that we have conducted an exhaustive inquiry into, or review of, all potentially available relevant information. These statements are inherently uncertain, and you are cautioned not to unduly rely upon these statements.

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SUMMARY OF RISK FACTORS

Below is a summary of material factors that make an investment in our securities speculative or risky. Importantly, this summary does not address all of the risks and uncertainties that we face. Additional discussion of the risks and uncertainties summarized in this risk factor summary, as well as other risks and uncertainties that we face, can be found under “Risk Factors” in Part I, Item 1A of this Annual Report on Form 10-K. This summary is qualified in its entirety by that more complete discussion of such risks and uncertainties. You should carefully consider the risks and uncertainties described under “Risk Factors” in Part I, Item 1A of this Annual Report on Form 10-K as part of your evaluation of an investment in our common stock.

•We are a late-stage clinical cell therapy company that has incurred substantial losses since our inception and anticipate that we will continue to incur substantial and increasing net losses for the foreseeable future.

•We will require substantial additional capital to achieve our goals, and a failure to obtain this necessary capital when needed could force us to delay, limit, reduce or terminate our product development or commercialization efforts.

•We currently have no products approved for sale and have never generated revenue from product sales. We may never generate revenue from product sales or achieve profitability.

•We operate in a rapidly evolving field and have a limited operating history, which may make it difficult to evaluate the success of our business to date and to assess our future viability.

•Our milestone, royalty and success payment obligations may result in dilution to our stockholders or may reduce the availability of our cash resources to satisfy the payment obligations, which could cause our operating results and financial condition to fluctuate significantly from quarter to quarter and year to year and may reduce the usefulness of our GAAP consolidated financial statements.

•If we are unable to successfully develop, manufacture and commercialize product candidates or experience significant delays in doing so, our business may be harmed.

•Our product candidates and technologies are based on novel technologies that are unproven and may not result in approvable or marketable products, which expose us to unforeseen risks and make it difficult for us to predict the time and cost of product development and potential for regulatory approval, and we may not be successful in our efforts to use and expand our technologies to develop any product candidate.

•The results of research, nonclinical studies or earlier clinical trials are not necessarily predictive of future results. If clinical trials of our product candidates fail to produce, or continue to produce, positive results or demonstrate satisfactory safety and efficacy, at the appropriate dose level or at all, we may incur additional costs or experience delays in completing, or ultimately be unable to complete, the development and commercialization of our product candidates.

•Clinical development involves a lengthy and expensive process with an uncertain outcome.

•Interim, topline or preliminary data from our clinical trials that we announce or publish from time to time may change as more patient data become available or as we make changes to our manufacturing processes and are subject to audit and verification procedures that could result in material changes in the final data.

•We acquired ImmPACT in October 2024 and LYL273 in November 2025 and may not realize the benefits of such acquisitions or any potential future collaborations, licenses, product acquisitions or other strategic transactions.

•We face substantial competition in a rapidly changing industry, which may result in others discovering, developing or commercializing products before or more successfully than we do.

•The manufacturing of cell therapies is very complex. We are subject to a multitude of manufacturing risks, any of which could substantially increase our costs, delay our programs or limit supply of our product candidates.

•Cell-based therapies rely on the availability of specialty raw materials, which may not be available to us on acceptable terms or at all.

•We currently manufacture drug products for our clinical trials ourselves. Delays in further qualifying or in receiving regulatory approvals for any manufacturing facility or product candidates, or in expanding our manufacturing capacity, could delay our development plans and thereby limit our ability to generate product revenues.

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•If our clinical manufacturing facility in Bothell, Washington or any of our potential contract manufacturing organizations is damaged or destroyed or production at these facilities is otherwise interrupted, our business would be negatively affected.

•We rely on third parties to assist in conducting and monitoring our clinical trials and for some of our research and non-clinical studies for our product candidates, and, if those third parties do not successfully carry out their contractual duties, comply with regulatory requirements or otherwise perform satisfactorily, we may not be able to obtain regulatory approval or commercialize product candidates, or such approval or commercialization may be delayed, and our business may be substantially harmed.

•We depend on the enrollment and retention of patients in our current and planned clinical trials for our product candidates. If we experience delays or difficulties enrolling or retaining patients in our clinical trials, our research and development efforts and business, financial condition and results of operations could be materially adversely affected.

•We do and will continue to or intend to rely on outside scientists and clinical trial investigators and their third-party research institutions for research and development and clinical testing of our product candidates. These scientists, investigators and institutions may have other commitments or conflicts of interest, which could limit our access to their expertise and harm our ability to leverage our technologies.

•We have in the past, and we may in the future, form or seek collaborations or strategic alliances or enter into additional licensing arrangements, and we may not realize the benefits of such alliances or licensing arrangements.

•We are currently in clinical development of our product candidates, and our future success is dependent on the successful development and regulatory approval of our product candidates and any product candidates we acquire.

•Our cell therapy product candidates represent new therapeutic approaches that could result in heightened regulatory scrutiny, delays in clinical development or delays in our ability to achieve regulatory approvals, commercialization or payor coverage of our product candidates.

•If we are unable to obtain and maintain sufficient intellectual property protection for our product candidates, or if the scope of the intellectual property protection is not sufficiently broad, our ability to commercialize our product candidates successfully and to compete effectively may be adversely affected.

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PART I

Item 1. Business.

Overview

We are a late-stage clinical cell therapy company advancing a pipeline of proprietary next-generation autologous chimeric antigen receptor (CAR) T-cell product candidates for patients with cancer. Our goal is to fully realize the curative potential of cell therapy for patients with hematologic malignancies and solid tumors. To achieve this, we are pioneering novel approaches designed to generate T‐cell therapies that drive long-lasting clinical responses. Our CAR T-cell product candidates start with the identification of promising cancer targets. We then engineer the patient’s own living immune cells and arm them with our innovative enhancements, including CAR constructs, technologies and manufacturing protocols that are designed to endow T cells with more potent cancer cell killing capabilities.

In hematologic malignancies, we are focused on delivering therapies that provide patients meaningfully improved outcomes over currently approved, first-generation CD19 CAR T-cell products. Our lead product candidate, rondecabtagene autoleucel (ronde-cel, also known as LYL314), is a dual-targeting CD19/CD20 CAR T-cell therapy designed to increase complete response rates and prolong the duration of response as compared to the approved CD19‐targeted CAR T-cell therapies. Ronde-cel is designed with a true ‘OR’ logic gate to target B cells that express either CD19 or CD20 with full potency and is manufactured with a process that enriches for CD62L‐positive cells to generate more naïve and central memory CAR T cells with enhanced stemlike features and antitumor activity.

We are currently conducting a pivotal single-arm clinical trial (PiNACLE) evaluating ronde-cel in patients with relapsed or refractory (R/R) large B-cell lymphoma (LBCL) receiving treatment in the third- or later-line (3L+) setting and a Phase 3 randomized controlled head-to-head CAR T-cell therapy trial (PiNACLE-H2H) for patients with LBCL receiving treatment in the second-line setting (2L). Patient dosing has commenced in the PiNACLE-H2H Phase 3 trial, which randomizes patients to either ronde-cel or investigator’s choice of axicabtagene ciloleucel (axi-cel) or lisocabtagene maraleucel (liso-cel).

To realize the potential of cell therapy for solid tumors, in November 2025 we acquired an exclusive global license for LYL273 (excluding mainland China, Hong Kong, Macau and Taiwan), an autologous guanylyl cyclase C (GCC)-targeted CAR T-cell product candidate previously known as GCC19CART, from Innovative Cellular Therapeutics Holdings Limited and Innovative Cellular Therapeutics, Inc. (together, ICT). A 67% overall response rate and an 83% disease control rate with a manageable safety profile have been reported at the highest dose level tested to date in patients with advanced metastatic colorectal cancer (mCRC) in a U.S. Phase 1 clinical trial as of the data cutoff date of October 28, 2025. LYL273 is enhanced with CD19 CAR expression and controlled cytokine release designed to improve CAR T-cell expansion, immune cell infiltration and cancer cell killing in the hostile tumor microenvironment. Clinical proof-of-concept for LYL273 was initially demonstrated in 15 patients with mCRC in an investigator-sponsored clinical trial conducted in China and published in JAMA Oncology (September 2024).

Our research scientists are also developing next-generation CAR T-cell product candidates for additional solid tumor indications enhanced with our anti-exhaustion and additional arming technologies and manufactured with our proprietary protocols. These enhancements are designed to endow CAR T cells with attributes needed to drive durable tumor cytolytic activity and achieve high rates of long-lasting clinical responses, including the ability to resist exhaustion, maintain qualities of durable stemness and function in the hostile solid tumor microenvironment.

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Our pipeline of next-generation CAR T-cell clinical product candidates targets cancers with large unmet need and is summarized in Table 1 below:

Table 1: Lyell’s Clinical Pipeline

Our Strategy

Lyell’s mission is to fully realize the curative potential of next-generation CAR T-cell therapies and meaningfully improve outcomes for patients with cancer. Today we are advancing next-generation innovative CAR T-cell therapies for patients with hematologic malignancies, including R/R LBCL, designed to improve outcomes over first‐generation products, and are aggressively progressing the next wave of cell therapy innovation for patients with solid tumors, including patients with advanced mCRC. To realize the potential of cell therapy for cancer, our product candidates target carefully selected tumor antigens or targets with high expression on cancer cells and low to no expression in normal tissues or that are inaccessible in normal tissues, to avoid on-target, off-tumor toxicity. We then arm our cells with enhancements to improve the CAR T cell’s ability to fight cancer. Specifically, we utilize enhancements, including the ability to resist exhaustion and maintain qualities of durable stemness, designed to improve the functional activity of T cells in the hostile tumor microenvironment to drive durable tumor cytolytic activity and achieve consistent and long-lasting clinical responses. Our product candidates are designed to be one-time CAR T-cell treatments that can achieve lasting remission for patients with cancer so they can return to their normal lives with extended disease-free, treatment-free periods.

Key components of our business strategy to achieve this goal include:

•Efficiently advance our lead late-stage clinical program evaluating ronde-cel for patients with LBCL— We believe our autologous dual-targeting CD19/CD20 CAR T‐cell product candidate, ronde-cel, has the potential to deliver improved, durable clinical outcomes for patients with R/R LBCL over first‐generation approved CD19 CAR T-cell therapies. Ronde-cel is currently under evaluation in a pivotal single-arm trial, PiNACLE, in the 3L+ setting. This trial is a seamless expansion of the 3L+ cohort in our ongoing Phase 1/2 clinical trial and is expected toenroll approximately 120 patients at approximately 25 sites. The primary endpoint is the best overall response rate. We havealso recently initiated the first-of-its-kind Phase 3 randomized controlled head-to-head CAR T-cell therapy clinical trial, PiNACLE-H2H. Patient dosing commenced in February 2026 in this trial, and site activation is underway in the United States, Canada and Australia. We expect to randomize approximately 400 patients 1:1 to either ronde-cel or investigator’s choice of axi-cel or liso-cel. The primary endpoint is event-free survival.

We recently reported updated clinical data in patients with aggressive LBCL in the 3L+- and 2L- settings from a multi-cohort multi-center Phase 1/2 clinical trial (NCT05826535) at the December 2025 American Society of Hematology Annual Meeting and Exposition (ASH 2025). The oral presentation included updated data from the 3L+ cohort (now the ongoing PiNACLE pivotal trial) including a best overall response rate of 93% and a complete response rate of 76% in 29 efficacy-evaluable patients with R/R LBCL. The median progression-free survival was 18 months as of the data cutoff date of September 5, 2025. Updated data were also presented from the 2L cohort, including 18 efficacy evaluable patients (94% with high-risk primary refractory disease) and demonstrated an 83% best overall response rate and a 61% complete response rate. The safety profile was

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appropriate for outpatient administration of ronde-cel. Data from 25 patients treated with ronde-cel and receiving dexamethasone prophylaxis revealed no reports of Grade 3 or higher cytokine release syndrome (CRS) and one case (4%) of Grade 3 or higher immune effector cell-associated neurotoxicity syndrome (ICANS).

•Efficiently advance our Phase 1 clinical program evaluating LYL273 for patients with advanced mCRC — We believe our autologous guanylyl cyclase C-targeting CAR T‐cell product candidate, LYL273 (previously known as GCC19CART), enhanced with CD19 CAR expression and controlled cytokine release designed to improve CAR T-cell expansion, immune cell infiltration and cancer cell killing in the hostile tumor microenvironment, has the potential to deliver improved, durable clinical outcomes for patients with advanced mCRC over currently approved therapies in the 3L+ mCRC setting. A 67% best overall response rate, an 83% disease control rate and an 8-month median progression-free survival with a manageable safety profile have been reported as of the data cutoff date of October 28, 2025. LYL273 is currently undergoing evaluation in an ongoing Phase 1 trial to establish the recommended Phase 2 dose.

•Advance novel targets and technologies to generate a robust pipeline of next-generation cell therapies designed to deliver durable antitumor activity for cancer indications with high unmet medical need and of substantial market size — We are committed to continuing the advancement of disruptive technologies designed to achieve the promise of cell therapy to significantly improve the outcome for patients with hematologic malignancies and solid tumors. Our objective is to select promising CAR T-cell therapy targets that are highly expressed on cancers that impact a large number of patients with high unmet medical need, but not on normal tissues to avoid on-target, off tumor toxicity. We then arm the CAR T cells with enhancements designed to optimize cancer cell killing. Specifically, our strategy centers around the utilization of enhancements, including the ability to resist exhaustion, maintain qualities of durable stemness and function in the hostile tumor microenvironment, designed to improve T cell functional activity, drive durable tumor cytolytic activity and achieve consistent and long-lasting clinical responses.

•Maintain state‐of‐the‐art infrastructure and expert capabilities to control and innovate cell product manufacturing— We have built and operate a dedicated manufacturing facility, the LyFE Manufacturing CenterTM (LyFE), that produces cell product for our clinical trials. At full staffing and capacity, we expect LyFE to have the capacity to manufacture more than 1,200 CAR T-cell doses/year and support commercial launch. We have invested in infrastructure that enables real‐time monitoring of our manufacturing processes and the ability to incorporate insights into our research, manufacturing and clinical development efforts. Our manufacturing strategy includes seeking new ways to efficiently, rapidly and cost-effectively scale manufacturing capacity for our cell product candidates for future clinical trials and potential commercialization.

•Generate, secure and defend intellectual property on our differentiated technology platforms, CAR constructs and product candidates— We have developed and secured a robust suite of intellectual property, including know-how, through our internal research efforts, licensing agreements and collaborations. We rigorously analyze, file and protect our intellectual property in various jurisdictions around the world in an ongoing manner.

•Opportunistically pursue strategic opportunities to maximize the potential of our pipeline and capabilities—We consider a variety of ways to collaborate with external partners. We evaluate options for partnering programs, indications or geographies with pharmaceutical or biotechnology companies for the development and/or commercialization of our product candidates designed to address large patient populations. We also consider opportunities to acquire or license rights or invest in differentiated product candidates or technologies to complement our pipeline.

Our Pipeline Clinical Programs

Rondecabtagene autoleucel (ronde-cel, also known as LYL314): A next-generation dual-targeting CD19/CD20 CAR T-cell product candidate designed to increase complete response rates and prolong the duration of responses as compared to the approved CD19‐targeted CAR T-cell therapies for the treatment of large B-cell lymphoma

Ronde-Cel: Target Market and Approved Therapies

Our lead program, ronde-cel, is targeting patients with aggressive R/R large B-cell non‐Hodgkin lymphoma (NHL), more commonly referred to as LBCL. Lymphoma is a blood cancer that begins in lymphocytes and spreads primarily in lymph nodes, but can also metastasize to the liver, kidney, brain and other organs. Lymphomas are broadly classified as either Hodgkin or non‐Hodgkin lymphoma, with NHL present in multiple groups of lymph nodes whereas Hodgkin lymphoma is typically located in a single group of lymph nodes, generally in the upper body. NHL is the more common form of lymphoma, representing approximately 90% of all lymphomas.

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We are initially focused on developing ronde-cel for the treatment of patients with NHL subtypes representing approximately 35% of the over 80,000 patients estimated to be diagnosed with NHL in the United States in 2025 and 545,000 patients worldwide. The NHL subtypes we are currently pursuing include diffuse large B-cell lymphoma (DLBCL), high grade B-cell lymphoma (HGBCL), primary mediastinal large B-cell lymphoma (PMBCL), transformed follicular lymphoma (tFL), transformed marginal zone B-cell lymphoma (tMZBCL), transformed mantle cell lymphoma (tMCL) and Grade 3B follicular lymphoma (FL3B). DLBCL represents approximately 31% of patients diagnosed with NHL each year (of which approximately 5% are HGBCL). PMBCL represents approximately 3% and FL3B and the transformed lymphomas represent approximately 1 to 2% of patients diagnosed with NHL each year. We may choose to further expand development to include additional NHL subtypes in the future.

Of the approximately 30,000 patients in the U.S. with LBCL, 40% to 50% are refractory to, or relapse following, first-line treatment and we estimate approximately 12,000 to 15,000 patients in the United States with LBCL progress to 2L treatment. We estimate the 3L+ patient population to be approximately 6,000 to 7,000 patients, including up to 50% of patients who progress on first-line therapy and receive a second chemotherapy regimen prior to CAR while awaiting referral and/or apheresis scheduling (Figure 1).

Figure 1: Ronde-cel is targeting the multi-billion dollar CD19 CAR T-cell market.

While the first generation of CD19 CAR T-cell therapies delivered a major advance in treatment for patients with B-cell lymphoma, there remains a need for therapies that deliver more complete and durable responses. More than 40% of patients with aggressive LBCL treated in the 3L+ setting with a CD19 CAR T-cell therapy are not disease-free after treatment and 30% of patients do not respond at all. Of these patients treated with an approved CD19 CAR T-cell therapy, approximately 50% of patients progress or die within six months, and the overall survival at one year for patients treated with a CD19 CAR T-cell therapy is only 50% to 60%. The median progression-free survival for the approved CD19 CAR T-cell therapies for patients in the 3L+-setting is 6 to 7 months. Importantly, the pivotal trials in the 3L+ setting for axi-cel and liso-cel did not enroll patients over the age of 75, and the axi-cel ZUMA-1 trial did not allow patients to receive bridging therapy between apheresis and CAR T-cell therapy infusion, potentially excluding patients who were progressing too rapidly to wait for CAR T-cell therapy manufacturing.

In the 2L setting, the ZUMA-7 randomized controlled trial of axi-cel versus standard of care chemoimmunotherapy did not enroll patients above the age of 75 and the only bridging therapy allowed was steroids. In ZUMA-7, the complete response rate was 65% and the median progression-free survival in all enrolled patients was 14.7 months. For those with primary refractory disease, the median progression-free survival was only 7 months. The complete response rate for patients with primary refractory disease was not reported. Liso-cel was evaluated in two pivotal trials conducted in the 2L setting. The first pivotal trial was a randomized controlled trial of liso-cel versus standard of care chemoimmunotherapy (TRANSFORM) which did not enroll patients over the age of 75, but did allow bridging therapy with chemotherapy. The complete response rate was 66% and the median progression-free survival was 14.8 months in the

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liso-cel arm. Data for patients with primary refractory disease in the 2L were not reported from this trial. The second pivotal single-arm trial conducted for liso-cel (PILOT), did allow patients over the age of 75 and included patients ineligible for transplant with primary refractory disease, relapse before 12 months or relapse after 12 months to enroll into the trial. The complete response rate in the overall patient population was 54% and was 42% in the primary refractory patient population. The package insert for YESCARTA® lists the rate of Grade 3 or higher CRS as 9% and the rate of Grade 3 or higher neurotoxicity as 31%. The package insert for BREYANZI® lists the rate of Grade 3 or higher CRS as 3% and the rate of Grade 3 or higher neurotoxicity as 10%.

The approved CD19 CAR T-cell therapies for NHL are expected to achieve worldwide sales in 2026 of approximately four billion dollars. YESCARTA® has been the market leader since approval, but recently BREYANZI® has been gaining market share, presumably due to lower rates of neurotoxicity. This “switching” behavior of CAR T-cell therapy prescribers has also been reported in the multiple myeloma market with CARVYKTI® taking market share from ABECMA®, presumably due to enhanced efficacy (Figure 2).

Figure 2: CAR T-cell therapy treating physicians have a historical willingness to “switch” CAR T-cell therapies based on the strength of efficacy and safety clinical data.

Ronde-Cel: Mechanism of Action

Ronde-cel is an autologous dual-targeting CD19/CD20 CAR T-cell therapy designed to kill B cells expressing CD19 and/or CD20 antigens for the treatment of patients with aggressive B-cell malignancies. We acquired this product candidate through our acquisition of ImmPACT Bio USA Inc. (ImmPACT) in October 2024.

A dual-targeting, or bispecific, tandem CAR recognizes two targets with a single construct. Ronde-cel is rationally designed with a true CD19/CD20 “OR” logic-gated CAR targeting either CD19 or CD20 with full potency, and the cell therapy product is enriched for naïve and central memory T cells. Together, this novel construct and the cell enrichment for naïve and central memory T cells are designed to provide multiple clinical benefits over CD19 CAR T-cell therapies, including:

•Ability to target lower or heterogeneous CD19 antigen density and result in a higher percentage of complete responses than with a single-targeting CAR construct;

•Increase in the duration of responses by preventing relapse due to CD19 antigen escape; and

•Better cell expansion, persistence and reduced exhaustion to provide longer duration of responses.

Ronde-cel consists of autologous T cells that are genetically modified through transduction with a lentiviral vector expressing a tandem CAR construct composed of anti-CD19 and anti-CD20 single-chain variable fragments (scFvs) in tandem and an intracellular portion that contains the T-cell signaling zeta chain (CD3-ζ) and the 4-1BB co-stimulatory domain (Figure 3). This differentiates ronde-cel from cell therapies and other therapeutic modalities that singularly target CD19, CD20 or CD22.

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Figure 3: Ronde-cel contains separate, tandem scFV antibody domains designed to target both CD19 and CD20 and is manufactured using a CAR construct that contains a 4-1BB costimulatory domain and is manufactured with a process to enrich for CD62L-positive naïve and central memory T cells.

Antigen heterogeneity, which refers to variation in the expression levels of tumor antigens across cancer cells, can limit the effectiveness of targeted therapies, including CD19 CAR T-cell therapy. Nonclinical data demonstrated that ronde-cel’s optimized tandem CAR design is capable of killing target cells that express CD19 only, CD20 only or both antigens with full potency, thus it has the potential to achieve a higher percentage of complete responses than a single‐targeting agent, particularly in those patients with malignant B cells with a lower or heterogeneous CD19 antigen density.

CD19 antigen escape, a mechanism by which tumor cells evade the host immune system or targeted therapy through loss, downregulation or modification of target antigens, is a known mechanism contributing to disease relapse. Ronde-cel’s dual-targeting of both CD19 and CD20 was designed to overcome CD19 antigen escape and potentially prolong the duration of responses, as well as to target malignant B cells with limited or no expression of CD19 to achieve a higher overall response rate. In a nonclinical xenograft model of mixed tumor cells (75% CD19-positive/CD20-positive, 25% CD19-negative/CD20-positive), mice treated with CAR T cells that targeted CD19 and CD20 in this manner eliminated tumors and overcame a subsequent tumor re-challenge, whereas CD19 CAR T-cell treatment failed to control the tumors.

Additionally, ronde-cel is manufactured to produce a CAR T-cell product with higher proportions of naïve and central memory T cells through a process that enriches for CD62L-expressing cells. CD62L is a surface protein that acts as a homing beacon, guiding white blood cells to sites of inflammation. CD62L enrichment in ronde-cel’s manufacturing process substitutes for the CD4/CD8 enrichment step in traditional CAR T-cell manufacturing, and generates cell products that are comprised of more than 95% naïve or central memory T cells. This manufacturing process is designed to generate CAR T cells with enhanced antitumor activity, which we believe could result in both increased complete response rates and more durable responses. Naïve T cells are mature T lymphocytes that have differentiated in the bone marrow and undergone central tolerance selection in the thymus, but have not interacted with their antigen. CAR T cells generated from these CD62L-positive less differentiated T cells have been associated with better cell expansion, improved persistence, reduced exhaustion and lower adverse cytokine production compared to CAR T cells generated from traditional processes. The enrichment of CD62L-expressing T cells does not increase the manufacturing time, which is similar to that of the approved CD19 CAR T-cell therapies with a median vein to site time of 16 days. Data from the ZUMA-7 pivotal trial of axi-cel in patients with R/R LBCL demonstrated an improved overall survival in those patients with a higher median percentage of T cells with a naïve/stem memory phenotype in the administered cell product.

During ASH 2025, we orally presented translational data from our ongoing Phase 1/2 clinical trial that showed that ronde-cel manufactured with CD62L-positive enriched cells achieved robust expansion and high expression of memory-related genes after infusion in patients with LBCL. An evaluation of ronde-cel and published data for approved CD19 CAR T-cell products demonstrated that ronde-cel had a higher proportion of CD62L-positive T cells with a higher proportion of memory-cell phenotype prior to infusion (ronde-cel, N = 34; axi-cel, N = 110; and tisagenlecleucel (tisa-cel), N = 31). In addition, ronde-cel had up to a three-fold higher expansion in patients after infusion compared to the expansion of approved CD19 CAR T-cell products. Ronde-cel product memory-cell phenotype was positively correlated with expansion. Peripheral blood samples collected from patients one month after infusion (N = 9) also had a higher proportion of CAR T cells with a memory phenotype compared to cells from axi-cel-treated patients (N = 4). Ronde-cel CAR-positive

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T cells collected from patients one (N = 7) and two months (N = 3) after infusion demonstrated sustained capacity to proliferate, kill tumor cells over 72 hours and secrete cytokines.

Ronde-Cel: Clinical Development Strategy

Our ongoing Phase 1/2 trial of ronde-cel is a multi-cohort, multi-center, open-label dose-escalation and dose-expansion clinical trial designed to evaluate the safety and clinical benefit of ronde-cel (NCT05826535). We presented positive data, detailed below, from the 3L+ and 2L cohorts from the ongoing Phase 1/2 trial during an oral presentation at ASH 2025. Based on these data, as well as our recent End-of-Phase 1 meetings with the U.S. Food and Drug Administration (FDA), we announced the initiation of two pivotal trials of ronde-cel: PiNACLE and PiNACLE-H2H.

The PiNACLE trial (Figure 4), which is underway and enrolling patients, is a seamless expansion of the 3L+ cohort of our Phase 1/2 trial. PiNACLE is a single-arm pivotal trial evaluating ronde-cel at a dose of 100 x 106 CAR T cells in patients with LBCL treated in the 3L+ setting. The trial is expected to enroll approximately 120 patients with R/R DLBCL, PMBCL, FL3B or tFL who have received two or more prior lines of therapy and have not received CAR T-cell therapy. Patients may be treated with ronde-cel in the inpatient or outpatient setting, with observation near the site limited to 14 days. There is no upper age limit for eligibility, which broadens the addressable patient population. The primary endpoint of the trial is the best overall response rate, including an evaluation of duration of response. More information about the PiNACLE trial can be found on clinicaltrials.gov (NCT05826535).

Figure 4: The PiNACLE single-arm pivotal trial schematic. The PiNACLE trial is expected to enroll approximately 120 patients with R/R LBCL. NCT05826536

CAR, chimeric antigen receptor; Cy, cyclophosphamide; DLBCL, diffuse large B-cell lymphoma; 3BFL, Grade 3B follicular lymphoma; Flu, fludarabine; PMBCL, primary mediastinal B-cell lymphoma.

The PiNACLE-H2H trial is a Phase 3 head-to-head CAR T-cell therapy randomized controlled trial that will evaluate ronde-cel versus investigator’s choice of approved CD19 CAR T-cell therapies (axi-cel or liso-cel) in patients with R/R LBCL receiving treatment in the 2L setting. Patients randomized to ronde-cel will be treated with a dose of 100 x 106 CAR T cells. The primary endpoint of the trial is event-free survival. The trial is expected to enroll approximately 400 patients with R/R LBCL (200 per arm), including DLBCL, PMBCL, HGBCL, FL3B, tFL, tMCL or tMZBCL who have not previously received CAR T-cell therapy. Patients may be treated with ronde-cel in either the inpatient or outpatient setting. Patient dosing commenced in February 2026, and clinical site activation is ongoing in the United States, Canada and Australia. More information about the PiNACLE-H2H trial can be found on clinicaltrials.gov (NCT07188558). Now that the PiNACLE-H2H trial is enrolling patients, the 2L cohort in our Phase 1/2 multi-cohort trial is no longer recruiting patients.

In the future, we may expand into other types of B-cell NHL.

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Figure 5:The PiNACLE-H2H Phase 3 randomized controlled head-to-head CAR T-cell therapy trial of ronde-cel versus investigator’s choice of axi-cel or liso-cel.

Ronde-Cel: Clinical Data

We presented new clinical and translational data from our ongoing Phase 1/2 clinical trial of ronde-cel in patients with LBCL at ASH 2025. The trial is a multi-cohort, multi-center dose-escalation, dose-expansion trial. Patients had not previously received CAR T-cell therapy and there was no upper age limit nor requirement for CD19/CD20 screening prior to enrollment. Data were presented from the 3L+ and 2L cohorts. Bridging therapy was optional and lymphodepletion included fludarabine, 30 mg/m2 and cyclophosphamide, 500 mg/m2, each for three days. The cell manufacturing median vein to site time was 16 days and the recommended Phase 2 dose was established at 100 x 106 CAR T cells. Two patients were treated at Dose Level 2 (300 x 106 CAR T cells). Imaging response assessments were conducted locally at Day 28, Month 3 and every three months for 24 months. The trial objectives were safety and tolerability, best overall response rate and complete response rate, duration of response, selection of the recommended Phase 2 dose and cell expansion pharmacokinetics.

Sixty-nine patients with R/R LBCL received ronde-cel as of September 5, 2025 (the data cutoff date for the presentation at ASH 2025). Patient demographics and baseline disease characteristics were consistent with a high-risk, heavily pre-treated patient population, particularly as compared to historical trials of CD19 CAR T-cell products: median ages of 64 and 65 years with 16% (6/37) and 21% (5/24) of patients being 75 years or older in the 3L+ and 2L settings, respectively; and primary refractory disease in 43% (16/37) and 92% (22/24) of patients in the 3L+ and 2L settings, respectively. The efficacy evaluable population, defined as those patients with Day 84 assessments or prior disease progression or death, consisted of 47 patients (29 in the 3L+ setting and 18 in the 2L setting).

Patients Treated with Ronde-Cel in the 3L+ Setting

There were 29 efficacy-evaluable 3L+ patients with R/R LBCL (DLBCL, PMBCL, 3BFL or tFL) with a median follow up time of 12 months as of the data cutoff date. The data are presented in Figure 6 and summarized here:

•The best overall response rate was 93% (27/29 patients), with 76% (22/29) of patients achieving a complete response

•72% (13/18) of patients with complete response remained in complete response at 6 months or longer

•Median progression-free survival was 18 months

The PiNACLE single-arm pivotal trial is a seamless expansion of this 3L+ cohort and is ongoing. The trial design is presented in Figure 4. Patients with HGBCL are no longer included in the PiNACLE single-arm trial to focus the trial on those patients most likely to achieve high durable response rates. The response rate and duration of response in patients enrolled with HGBCL (N = 8) was shorter than that observed for patients with other histologies.

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Figure 6: High rates of durable complete responses were observed in patients treated with ronde-cel in the 3L+ setting.

3L+, third- or later-line setting, LBCL, large B-cell lymphoma.

Patients Treated with Ronde-Cel in the 2L Setting

There were 18 efficacy-evaluable patients enrolled in the 2L setting with a median follow-up time of 9 months as of the data cutoff date. Of these efficacy-evaluable patients, 94% had primary refractory disease. Data from these patients are presented in Figure 7 and summarized here:

•The overall response rate was 83% (15/18 patients), with 61% (11/18) achieving a complete response

•70% (7/10) of patients with complete response remained in complete response at ≥ 6 months

•The median duration of complete response was not reached

Figure 7:High rates of durable complete responses were observed in patients treated with ronde-cel in the 2L setting.

2L, second-line setting, LBCL, large B-cell lymphoma.

Safety Data

In 69 patients, including all patients from both the 3L+ and the 2L cohorts, a manageable safety profile appropriate for outpatient administration was observed. No Grade 3 or higher CRS was observed. Twenty-five of the 69 patients received protocol-directed dexamethasone prophylaxis (10 mg/day for 3 days). One case (4%) of Grade 3 or higher ICANS was reported in a patient with high disease burden; no case of Grade 2 ICANS was reported.

In all 69 patients, as of the data cutoff date, low rates of Grade 1 (32%) or Grade 2 (29%) CRS were reported; ICANS rates were reported as follows: Grade 1 (9%), Grade 2 (3%) and Grade 3 or higher (12%) of patients. The median time to complete resolution of all reports of ICANS was 4 days. Cell pharmacodynamic data demonstrated robust CAR T‐cell expansion and persistence that were similar in patients with or without dexamethasone prophylaxis. No deaths were determined to be related to ronde-cel administration. Data are presented in Figure 8.

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Figure 8:Adverse events of interest with and without dexamethasone prophylaxis for patients in both the 3L+ and 2L settings.

CRS, cytokine release syndrome; HGBCL, high grade B-cell lymphoma; ICANS, immune effector cell-associated neurotoxicity; IEC-HS, immune effector cell-associated hemophagocytic lymphohistiocytosis-like syndrome; IV, intravenous; LDH, lactate dehydrogenase; PO, per os (oral).

Pharmacokinetic Data

Pharmacokinetic data evaluating ronde-cel cell expansion using the droplet digital polymerase chain reaction (ddPCR) method are presented in Figure 9. The data showed robust cell expansion with or without dexamethasone prophylaxis (dexamethasone 10 mg by oral or intravenous administration once daily for 3 days) with no significant differences observed in peak CAR T-cell expansion (Cmax) or overall exposure (AUC) between patients who received dexamethasone (N = 25) and those who did not (N = 42).

Figure 9: Ronde-cel cell expansion was robust in patients who did or did not receive dexamethasone prophylaxis, 10 mg by oral or intravenous administration daily for three days.

CAR, chimeric antigen receptor; ddPCR, digital droplet polymerase chain reaction; DNA, deoxyribonucleic acid; IQR, interquartile range; LLOQ, lower limit of quantitation; LLOD, lower limit of detection.

Assay used for measuring B cells/μl (Epiontis ID®) can detect as low as 2 cells/μl with high accuracy.

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Ronde-cel has received Regenerative Medicine Advanced Therapy designation as well as Fast Track designation from the FDA for the treatment of adults with R/R DLBCL in the 3L+ setting and has also received RMAT designation for the treatment of LBCL in the 2L setting. The FDA has also granted ronde-cel Orphan Drug Designation for the treatment of DLBCL/HGBCL with MYC and BCL2 rearrangements.

Based on the clinical data observed to date and an End-of-Phase 1 meeting with the FDA, we have initiated the Phase 3 randomized controlled head-to-head CAR T-cell trial evaluating ronde-cel versus investigator’s choice of an approved CD19 CAR T-cell therapy (axi-cel or liso-cel).

LYL273 (formerly known as GCC19CART): Guanylyl cyclase C-targeted CAR T-cell product candidate for the treatment of mCRC and other GCC-expressing cancers

We acquired an exclusive global license, outside of mainland China, Hong Kong, Macau and Taiwan, from ICT for a next-generation GCC-targeted CAR T-cell product candidate (LYL273, formerly GCC19CART) with promising dose-dependent clinical activity, including a 67% best overall response rate, disease control rate of 83% and a median progression-free survival of 8 months in patients with advanced mCRC in a Phase 1 trial conducted in the U.S. The U.S. Investigational New Drug (IND) and Phase 1 trial initiation were supported by single-center data from an investigator‐sponsored study of 15 patients conducted in China and published in JAMA Oncology in 2024. LYL273 is a GCC-targeted CAR T-cell product candidate enhanced with CD19 CAR expression and controlled cytokine release designed to improve CAR T-cell expansion, immune cell infiltration and cancer cell killing in the hostile solid tumor microenvironment. LYL273 was granted Fast Track designation for the treatment of mCRC by the FDA.

LYL273: Target Market and Approved Therapies

Colorectal cancer is the second leading cause of cancer deaths worldwide, and the incidence of colorectal cancer is rising in people younger than 55 years old. In the United States, there were estimated to be 154,000 total new colorectal cancer diagnoses and about 1 in 5 of these diagnoses will occur in people younger than 55 years old. Approximately 53,000 people were expected to die from CRC in the U.S. in 2025. Approximately 25% of patients have metastatic disease at the time of diagnosis and up to 60% of patients diagnosed with colorectal cancer will develop distant metastases at some point during their disease journey.

Despite the remaining tremendous unmet medical need for new effective therapies for mCRC, the worldwide net sales for currently approved CRC products is expected to reach 12 billion dollars by 2032 (Figure 10). However, the benefit of approved therapies for mCRC in the 3L+ setting is limited.With the approved products, only six percent or less of patients achieve a partial or complete response to their next line of therapy, the median progression-free survival is 6 months or less and the median overall survival is 11 months or less (Figure 10).

Figure 10:The worldwide market for therapies approved for colorectal cancer is six billion dollars and growing. However, currently approved standard-of-care therapies in the 3L+ setting do not achieve meaningful response rates and provide limited survival benefit.

LYL273:Mechanism of Action

LYL273 is a GCC-targeted CAR T-cell therapy armed with enhancements including CD19 CAR expression and release of multiple cytokines in a controlled manner upon T-cell activation. Together, these enhancements were designed to increase CAR T-cell expansion, immune cell infiltration and cancer cell killing (Figure 11). GCC is a receptor that plays a key role in the regulation of intestinal electrolyte homeostasis. It is expressed on more than 95% of colorectal cancers and a majority of pancreatic adenocarcinomas. Its expression in healthy tissue is limited to the gastrointestinal tract, where it is sequestered by tight junctions from the circulation.

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There are currently no CAR T-cell therapies approved to treat patients with solid tumors.LYL273 was specifically designed to overcome two key barriers that have previously prevented successful treatment of solid tumors with CAR T‐cell therapies. The first is lack of sufficient in vivo CAR T-cell expansion to allow for adequate tumor infiltration. The second is inhibition of antitumor activity such as tumor cell killing and cytokine production due to the hostile tumor immunosuppressive or “cold” tumor microenvironment. GCC is an excellent target because it is highly expressed in the vast majority of colorectal cancers and metastases and expressed at lower levels in normal gut tissue and generally inaccessible to the circulation. However, our approach is to arm CAR T-cell therapies with additional enhancements to increase the CAR T cell’s ability to kill cancer cells.

LYL273 is a single product consisting of a mixture of three key cell types: GCC CAR T cells, CD19 CAR T cells that release specific cytokines upon activation and doublet cells that have both GCC and CD19 CAR expression. Upon activation, these doublet cells are also engineered to release either interferon gamma (IFNγ), interleukin 12 (IL-12) or interleukin-6 (IL-6). The CD19 CAR expressing T cells engage B cells and jumpstart CAR T-cell activation and cell expansion upon infusion. As the CAR T cells infiltrate into the cancer, the cytokines enhance further cell expansion, remodel or “warm up” the suppressive tumor microenvironment and enhance immune cell infiltration and cancer cell killing. The level of cytokines is carefully regulated by specific vector design and usage during manufacturing. The Miltenyi CliniMACS PRODIGY® closed, automated manufacturing system is used to manufacture LYL273 and it is a standardized 7-day manufacturing process that is easily transferable and scalable.

A. B.

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Figure 11: A. LYL273 is a GCC-targeted CAR T-cell product candidate armed with enhancements including CD19 and the controlled release of cytokines including IFNγ, IL-12 and IL-6. B. It is a single product enhanced with three key CAR T-cell types including GCC CAR T cells, CD19 CAR T cells that release cytokines upon activation and engagement of B cells. C. LYL273 is designed to enhance in vivo cell expansion and to remodel the tumor microenvironment to improve tumor infiltration and cancer cell killing.

LYL273: Clinical Development Strategy

LYL273 is under evaluation in an ongoing Phase 1 clinical trial to determine the recommended Phase 2 dose and regimen, and to determine the tolerability and pharmacokinetics of LYL273. The IND was filed and the trial initiated based upon 15 patients with refractory mCRC from an investigator-sponsored study in China published in JAMA Oncology, 2024. Patients were evaluated at either Dose Level 1 (1 x 106 CAR-positive cells/kg; N = 8) or Dose Level 2 (2 x 106 CAR‐positive cells/kg; N = 7). Across both dose levels, the overall response rate was 40% (6/15). The disease control rate was 73%. At Dose Level 2, the median overall survival was 25 months (95% confidence interval [CI] of 13.4 to 26.1) and the median progression-free survival was 6 months (95% CI, 3.0 to not applicable). No deaths occurred during the study period. Adverse events of interest included CRS (86%, Grade 1 or 2), ICANS (14%, Grade 4), diarrhea (57%, Grade 3, all resolved), leukopenia (57%, Grade 3). Prior to these data, ICT reported unpublished data in 20 patients at various doses with various manufacturing processes across multiple different centers in China. During the study treatment period, five deaths were reported at these trial sites. The trial was subsequently focused at one expert center with CAR T-cell therapy experience.

LYL273: Clinical Data

Response Rates

The U.S. Phase 1 clinical trial is ongoing at four centers in the United States, including the Dana Farber Cancer Institute, the University of California, San Francisco Comprehensive Cancer Center, the University of Colorado Cancer Center and the City of Hope Comprehensive Cancer Center. Patients with refractory mCRC treated with fluoropyrimidine-, oxaliplatin- and irinotecan-based chemotherapy, an anti-vascular endothelial growth factor therapy and anti-epidermal growth factor receptor therapy for RAS wild-type tumors and checkpoint inhibitor treatment for microsatellite-instability high or mismatch repair deficient tumors are eligible if they have one measurable lesion per Response Evaluation Criteria for Solid Tumors, version 1.1. Liver metastases are allowed, but limited to no more than seven lesions with the largest lesion less than 3 cm. The patient must be determined to have no surgical options with curative intent. A single dose of lymphodepleting chemotherapy consisting of cyclophosphamide, 300 mg/m2, and fludarabine, 30 mg/m2 is administered prior to CAR T-cell infusion.

Two dose levels have been evaluated as of the data cutoff date of October 28, 2025 and include Dose Level 1 at 1 x 106 CAR T cells/kg (N = 6 patients) and Dose Level 2 at 2 x 106 CAR T cells/kg (N = 6 patients). The patients enrolled had a median age of 49 (range, 39 to 57), had a median of 3 prior lines of therapy (range, 2 to 6), with 25% receiving prior treatment with LONSURF® and 100% receiving prior treatment with AVASTIN®. All patients were microsatellite stable and 33% had disease with RAS mutations.

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The best overall response rate was 50% (6 of 12 patients) and the disease control rate was 83% across both dose levels. At Dose Level 2, the highest dose tested, the best overall response rate was 67%, including one patient with a pathological complete response, one patient with complete reduction in tumor volume of the target lesions (100% partial response) and two additional patients with confirmed partial responses (Figure 12). For patients treated at Dose Level 2, the disease control rate was 83%, and the median progression-free survival was 7.8 months.

Figure 12: In a U.S. Phase 1 clinical trial, the overall response rate was 50% (6 of 12 patients) and the disease control rate was 83% across both dose levels. At Dose Level 2, the highest dose tested, the overall response rate was 67%, including one patient with a pathological complete response, one patient with complete reduction in tumor volume of the target lesions (100% partial response) and two additional patients with confirmed partial responses. For patients treated at Dose Level 2, the disease control rate was 83%, and the median progression-free survival was 7.8 months.

Safety Data

In this trial, the incidence and severity of treatment-related adverse events were highest at Dose Level 2, where the most common adverse events were cytokine release syndrome in 83% (5/6) of patients (Grade 1, 67%; Grade 2, 17%) and diarrhea in 83% (5/6) of patients (Grade 1, 33%; Grade 2, 33%; Grade 3, 17%) as of the data cutoff date of October 28, 2025. The median duration of diarrhea was 11 days. Immune effector cell-associated neurotoxicity syndrome occurred in 33% (2/6) of patients (Grade 2, 17%; Grade 3, 17%) and resolved rapidly with treatment. One patient experienced a dose‐limiting toxicity at Dose Level 2, including Grade 3 diarrhea, Grade 4 enterocolitis and death from fungal sepsis 48 days post-infusion. No Grade 3 or higher diarrhea occurred in the last three patients treated since establishing an optimized management protocol for diarrhea, including prophylaxis with vedolizumab, infliximab and budesonide.

Pharmacokinetic Data

LYL273 is a single product candidate consisting of a mix of three key cell types including GCC CAR T cells, CD19 CAR T cells and GCC/CD19 doublet CAR T cells.A consistent cell expansion profile was observed across patients, as exemplified by the cell expansion data from Patient 11 who achieved a 100% partial response (Figure 13).All three cell types expanded, with the high level of expansion observed in the doublet cell population which accounted for more than 80% of all GCC CAR-expressing T cells at peak. After 21 days, the steadily expanded GCC CAR T cells made up the majority CAR T cells in peripheral blood.

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Figure 13: LYL273 cell expansion data from Patient 11 in the U.S. Phase 1 clinical trial. The plot shows the proportion of T cells in the peripheral blood of each of the three key cell types comprising LYL273.

Our Nonclinical Programs

Cell therapy has demonstrated profound results in some patients suffering from hematologic malignancies, but there remains a need for therapies that deliver more complete and durable responses. Solid tumors are even more complex and have evolved multiple mechanisms to evade and ultimately resist clearance by the immune system. This has limited the use of cell therapy in solid tumors, which account for 90% of cancer deaths. And while there has been recent progress with new cell therapies approved for solid tumors, overall response rates and the duration of response remain low.

We continue to invest in earlier stage cell therapy research and development utilizing our proprietary technologies. We are advancing a fully-armed solid tumor CAR T-cell product candidate with an undisclosed target, with the CAR T cells enhanced by multiple technologies, each designed to address different barriers to effective cell therapies, including T‐cell exhaustion, lack of durable stemness, as well as immune suppression within the hostile tumor microenvironment.

Our T-cell Enhancement and Manufacturing Technologies

For our solid tumor nonclinical pipeline, we are targeting large markets with substantial unmet medical need. We carefully evaluate and select CAR targets to ensure that binding to normal tissues is limited and manageable for safety. Selecting an appropriate antigen target and designing a potent CAR construct, however, are necessary but insufficient for achieving durable clinical responses in most solid tumors. Based on nonclinical evidence and clinical data, we believe there are multiple mechanisms limiting the efficacy and durability of cell therapy for solid tumors. T cells require three different types of signals for optimal immune activation:

•Signal 1: Antigen-specific recognition + CD3ζ (zeta) chain

•Signal 2: Co-stimulation such as with CD28 or 4-1BB to augment Signal 1

•Signal 3: Cytokine signaling

Our aim in designing a fully-armed CAR T-cell candidate is to optimize each signaling pathway with one or more enhancements from our suite of novel technologies to optimize CAR T-cell activation and function. Our next-generation CAR T-cell product candidates are fully-armed, meaning they incorporate multiple technologies, each designed to address different efficacy barriers to cell therapies for solid tumors, including T‐cell exhaustion, lack of durable stemness and insufficient cell expansion, as well as immune suppression within the hostile tumor microenvironment. Our technologies and manufacturing approaches, designed to enhance CAR T-cell function so they can achieve potent and durable cancer cell killing, are summarized in Table 2.

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Table 2: Lyell CAR T-Cell Enhancements Designed to Augment the Potency and Durability of our CAR T-Cell Product Candidates.

Lynn, R. et al., Nature, 2019; Chen, J. et al., Nature, 2019; Cheung A. et al., Nature Biotechnology 2018; Li A. et al., Scientific Reports 2024; Arcangeli et al., JCI 2022, Sommermeyer et al., Leukemia 2016, Chen et al., Cancer Discovery 2021, Aldoss et al., Clin Cancer Res 2023. AP-1, activator protein-1; CAR, chimeric antigen-receptor; NR4A3, nuclear receptor 4A3; TGF-β, transforming growth factor beta, TME, tumor microenvironment.

Two of our technologies, c-Jun overexpression and our Epi-R manufacturing protocol, have been clinically validated in a Phase 1 trial in patients with triple-negative breast cancer, and we are advancing an additional anti‐exhaustion technology, knockout of NR4A3 by gene editing, that has demonstrated even more potent antitumor functionality in nonclinical models. More recently, we have explored new strategies to express novel chimeric proteins to improve CAR T-cell killing in the hostile tumor microenvironment.

c-Jun Overexpression

Overexpression of c-Jun is based on the work of our co-founder, Crystal Mackall, M.D., the Ernest and Amelia Gallo Family Professor of Pediatrics and Medicine at Stanford University (Stanford) and Founding Director of the Stanford Center for Cancer Cell Therapy. Dr. Mackall discovered that exhausted T cells have an imbalance in the AP‐1 family of transcription factors, and that correcting for this imbalance by overexpression of c-Jun enables T cells to resist exhaustion, infiltrate solid tumors, and maintain their functionality and potency. This work was fully described in a Nature publication in 2019. Overexpression of c-Jun was recently validated in a Phase 1 clinical trial where a ROR1-targeted CAR T-cell product overexpressing c-Jun demonstrated clinical responses, improved pharmacokinetics, less CAR T-cell exhaustion and CAR T-cell tumor infiltration on histologic examination of on-study tumor biopsies. These data demonstrated improvement over the clinical data from a prior trial conducted at the Fred Hutchinson Cancer Center (Fred Hutch) of a similar ROR-1 CAR T-cell product, but without c-Jun overexpression, in a similar patient population where no responses were observed after a single CAR T-cell treatment and high levels of CAR T-cell exhaustion occurred rapidly.

NR4A3 Gene Knockout

NR4A3 gene knockout builds on the approach of reprogramming the AP-1 transcription factor pathway to delay exhaustion and improve antitumor function. We and others have previously observed that the NR4A family of transcription factors is upregulated in exhausted T cells and may contribute to T‐cell exhaustion, in part by restricting the activity of AP-1. We hypothesize that disruption of NR4A3 expression, along with c-Jun overexpression, may further unleash the potential for maximal c-Jun activity and endow greater functional resistance to exhaustion. Our nonclinical data suggest the combination of these two technologies, NR4A3 gene knockout and c-Jun overexpression, can act in a complementary fashion and may have the potential to further improve the potency and durability of our CAR therapy.

Epi-R Manufacturing Protocol

Epi‐R is our proprietary ex vivo manufacturing protocol that is designed to generate populations of stemlike T cells with reduced exhaustion and improved proliferation and antitumor activity. T cells with properties of durable stemness have an increased ability to self-renew and persist to drive durable tumor cytotoxicity. We developed this technology based upon the science conducted at the National Cancer Institute, where it was demonstrated that products with more and functional T cells can be achieved by altering the metabolic state of the cells during expansion.

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CD62L-Positive Enrichment

Our lead product candidate, ronde-cel, is manufactured with a process that enriches for CD62L-positive cells. This manufacturing process is designed to generate CAR T cells with enhanced antitumor activity that we believe could result in both higher complete response rates and more durable responses. Naïve T cells are CD62L-positive mature T lymphocytes that have differentiated in the bone marrow and undergone central tolerance selection in the thymus, but have not interacted with their antigen. CAR T cells generated from these CD62L-positive less differentiated T cells have been associated with better cell expansion, improved persistence, reduced exhaustion, and lower cytokine production compared to CAR T cells generated from traditional processes. The enrichment of CD62L-positive T cells does not increase the manufacturing time, which is similar to that of the approved CD19 CAR T-cell therapies.

Dual CAR Expression

Our clinical candidates are designed to target more than a single antigen. Ronde-cel expresses a tandem “OR” gated CAR to target both CD19 and CD20 that are expressed on B-cell lymphoma. This approach was designed to improve the complete response rate, as well as durability of response for patients with aggressive lymphoma. LYL273 is composed of several key CAR T-cell populations, including a novel doublet CAR T-cell population that expresses both GCC-targeted and CD19-targeted CARs. Upon infusion, expression of the CD19 CAR enables B-cell engagement that jumpstarts doublet CAR T-cell activation, cytokine release and cell expansion. Improved expansion may facilitate tumor infiltration and cancer cell killing.

Undisclosed New Technologies

In the solid tumor setting, CAR T cells need to overcome the suppressive tumor microenvironment to optimally kill cancer cells. We believe two key approaches to achieve this are to provide resistance to inhibitory signals such as TGF–β, and to enable locally-released supportive cytokine signaling to enhance the antitumor functionality of the CAR T cells. Our nonclinical research activities explore stacking our proprietary anti-exhaustion technologies with these additional approaches via the expression of novel chimeric proteins and vector design to generate fully-armed CAR T-cell product candidates.

Our Manufacturing Capabilities

We believe it is critically important to control and continuously monitor all aspects of the cell therapy manufacturing process to mitigate risks, including challenges in managing production, supply chain, patient material chain of custody and quality control. As we developed our technologies, we made a strategic decision to invest in building our own manufacturing facility to control our supply chain, maximize efficiencies in cell product production time, optimize cost and quality, protect proprietary aspects of our reprogramming technologies, and have the ability to rapidly incorporate advancements and new innovations. We view our manufacturing team and capabilities as a significant competitive advantage.

Our LyFE Manufacturing CenterTM located in Bothell, Washington is approximately 73,000 square feet and is comprised of manufacturing suites, laboratories and offices. LyFE is manufacturing ronde-cel for the pivotal PiNACLE and PiNACLE-H2H trials and the ongoing Phase 1/2 clinical trial for patients with R/R LBCL and, upon successful transition of manufacturing from ICT, is expected to manufacture LYL273 for the ongoing U.S. Phase 1 clinical trial for patients with advanced mCRC. At full staffing and capacity, we expect to be able to manufacture more than 1,200 patient CAR T‐cell products/year and support our clinical development needs for ronde-cel, LYL273 and other pipeline programs, as well as early commercial launch of ronde-cel and LYL273, if approved. LyFE was commissioned and designed to be in compliance with U.S. and European Union (EU) current Good Manufacturing Practices (cGMP) standards and has a flexible and modular design enabling T-cell therapies and cGMP viral vector production to control and de-risk the manufacturing sequence and timing of the major components of our supply chain. Owning our own facility has enabled seamless collaboration across research, process development and manufacturing for high-quality reproducibility at manufacturing scale.

We are focused on maintaining a manufacturing strategy that is operationally efficient to maximize our capacity and avoid any disruption to clinical trial supply.

Competition

The pharmaceutical industry is highly competitive and dynamic, owing to rapidly advancing technologies. We face potential competition from many different sources, including major pharmaceutical, specialty pharmaceutical and biotechnology companies, academic institutions, government agencies and public and private research institutions. Any product candidates that we successfully develop and commercialize will compete with existing treatments and new treatments that may become available in the future. In addition, during development and clinical trials, our product

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candidates may compete against other experimental treatments, whether cell therapy or other modalities, for patients with certain histologies or patients with tumors expressing certain antigen targets of interest.

If approved, ronde-cel will need to compete against other products approved in the 2L and 3L+ settings in our approved indications, including approved CD19 CAR T‐cell therapies, monoclonal antibodies targeting CD19, antibody‐drug conjugates, bispecific antibodies and selective inhibitors of exportin 1.

If approved, LYL273 will need to compete against other products approved in the 3L+ setting in our approved indications such as mCRC, including any approved kinase inhibitors, antibody-drug conjugates, cytotoxic chemotherapies and immunotherapies.

We are also aware of a number of companies using autologous or allogeneicCAR T-cell therapy approaches to treat hematologic malignancies and solid tumors.

Some of the companies developing competitive products have substantially greater financial and other resources than we have, such as larger research and development staff and well-established marketing and sales forces, or operate in jurisdictions where we do not have staffing or resources.

CAR T‐cell therapies for the treatment of hematologic malignancies and solid tumors are being developed by a number of companies, including but not limited to Agenus Inc., Akeso, Inc., Arcellx, Inc., Allogene Therapeutics, Inc., Arsenal Biosciences, Inc., AstraZeneca plc, Autolus Therapeutics plc, Bristol Myers Squibb Co., Caribou Biosciences, Inc., Gilead Sciences Inc., Immunocore Holdings plc, Johnson & Johnson, Nanjing Legend Biotech, Novartis AG, Pfizer Inc., Poseida/F. Hoffmann-La Roche AG and Summit Therapeutics Inc. We are also aware that other companies are developing therapies in modalities such as bispecific antibodies for B-cell lymphomas, including AstraZeneca, F. Hoffmann-La Roche AG and Amgen Inc. New treatments for colorectal cancer that may change the therapeutic landscape, including bispecific antibodies like PD-1/VEGF or PD-1/CTLA-4 bispecifics, are being developed by companies such as Summit Therapeutics, AbbVie, Akeso, Agenus, and Pfizer. CytomX has moved beyond dose escalation in a Phase 1 trial for a novel masked, conditionally activated antibody-drug conjugate directed againstepithelial cell adhesion molecule under evaluation in patients with colorectal cancer.

Among companies developing CAR T-cell therapies for hematologic malignancies and solid tumors, we believe we are substantially differentiated by our technologies, manufacturing protocols, capabilities, knowledge, experience, scientific personnel and robust intellectual property portfolio. We believe there are many factors affecting the success of any of our product candidates, including efficacy, safety, accessibility, price and scale and cost of manufacturing.

License and Collaboration Agreements

UCLA License Agreement

As a result of our October 2024 acquisition of ImmPACT, we acquired rights and assumed obligations under a license agreement with the Regents of the University of California, acting through The Technology Development Group of UCLA, dated February 18, 2021, as amended (the UCLA License Agreement). Pursuant to the UCLA License Agreement, UCLA granted us (i) an exclusive, royalty‐bearing license, with the right to sublicense through a specified number of tiers, under certain patent rights owned by UCLA and certain patent rights co‐owned by UCLA and the Seattle Children’s Hospital doing business as the Seattle Children’s Research Institute (SCRI) and (ii) a non‐exclusive, royalty‐bearing license, with the right to sublicense through a specified number of tiers, under related technical information, in each case related to our CD19/CD20 program, for the development, use and sale of products or services associated with certain inventions made in the course of research by UCLA and SCRI in all fields of use. In accordance with the Patent and Trademark Law Amendments Act (the Bayh‐Dole Act), UCLA granted the U.S. federal government a non‐exclusive, non‐transferable, irrevocable, paid‐up license to the licensed patents.

Under the UCLA License Agreement, we are obligated to diligently develop and commercialize licensed products and to achieve certain development, regulatory and commercialization diligence milestones. If, subject to our right to extend such diligence milestones in certain circumstances, we are unable to meet our diligence obligations and do not agree with UCLA to modify such obligations, UCLA has the right and option to either terminate the license agreement or convert the granted rights to a non‐exclusive license. We are also required, subject to certain exceptions, to provide UCLA with an affordable access plan within a specified time following the first commercial sale of a licensed product that is intended to support affordable access to licensed products in certain low‐ and middle‐income countries and other countries in which we do not intend to commercialize licensed products.

UCLA and SCRI reserved, for themselves and for other nonprofit and academic research institutions, their rights to use the patent rights and technical information licensed to us for education and research purposes and to publish results arising therefrom, and for UCLA to offer and perform clinical diagnostic and prognostic services for patients in the

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University of California healthcare system, in each case subject to certain exclusions. Our rights under the UCLA License Agreement are also subject to certain government rights.

Under the UCLA License Agreement, ImmPACT paid UCLA a small upfront license issue fee and, upon our assumption of the agreement in connection with our acquisition of ImmPACT, we are obligated to pay a nominal, tiered annual license maintenance fee each year of the term until we make the first commercial sale of a licensed product. Upon the achievement of specified development, regulatory and commercial milestones, we are obligated to pay UCLA one-time milestone payments of up to an aggregate amount in the mid-single digit millions for each commercialized licensed product. In addition, we are obligated to pay UCLA a tiered royalty on worldwide annual net sales of any commercialized licensed products in the low‐ to mid-single digits percentage, subject to specified and capped reductions and a tiered minimum annual royalty payment of between a low-five figure and a low-six figure amount. ImmPACT reimbursed UCLA for all patent costs incurred prior to the effective date of the UCLA License Agreement, and we are obligated to reimburse UCLA for all patent costs incurred by them during the term of the license agreement.

The UCLA License Agreement will expire, on a product-by-product and country-by-country basis, on the later of (a) the expiration of the last to expire valid claim of the patent rights covering such product in such country and (b) ten (10) years after the date of the first commercial sale of such product in such country. UCLA has the right to terminate the agreement in the event of our uncured material breach, subject to a specified notice and cure period, or upon certain insolvency events. We may terminate the agreement for convenience, subject to a specified notice period.

ICT License Agreement

On November 6, 2025, we entered into an Exclusive License Agreement with ICT for the development and commercialization of LYL273, a novel GCC-targeted CAR T-cell product candidate for the treatment of mCRC and other GCC-expressing cancers (the ICT License Agreement). Pursuant to the terms of the ICT License Agreement, we received exclusive global rights, outside of mainland China, Hong Kong, Macau and Taiwan, to research, develop, manufacture, commercialize and otherwise exploit certain product candidates and products, including LYL273, worldwide in exchange for an upfront payment of $40 million in cash and the issuance of 1.9 million shares of our common stock. In addition, ICT is eligible to receive additional cash and equity payments of (i) a potential $30 million clinical milestone payment, up to $115 million upon the achievement of certain late-stage regulatory milestones and up to $675 million in commercial sales milestones; (ii) up to an additional 1.85 million shares of our common stock based on the achievement of certain clinical and regulatory milestones; and (iii) tiered royalties ranging from mid-single-digits up to 10% on annual net sales in the United States and low- to mid-single-digit royalties on annual net sales in other countries within the licensed territory.

The ICT License Agreement includes customary representations, warranties and covenants, including, but not limited to, covenants by us and ICT to conduct the research, development, manufacture, commercialization and other exploitation of the product candidates and products, and their other obligations under the ICT License Agreement, in compliance with the terms of the ICT License Agreement and all other applicable laws and marketing approvals.

The ICT License Agreement may be terminated, among other circumstances, (i) by either party for uncured material breach, (ii) by either party due to the insolvency of the other party, (iii) by us for safety or regulatory reasons or (iv) by us on a product-by-product and country-by-country basis in our sole discretion after providing certain notice.

The ICT License Agreement (and any right or obligation thereunder) may not be assigned without the prior written consent of the other party, except to an affiliate or third party that acquires the business of the assigning party by way of a merger or sale of assets.

Intellectual Property

We strive to protect and enhance the proprietary technology, inventions and improvements that are commercially important to our business, including seeking, maintaining and defending patent rights, whether developed internally or licensed from our collaborators or other third parties. We seek to protect our proprietary position by, among other methods, filing patent applications in the United States and in jurisdictions outside of the United States related to our proprietary technology, inventions, improvements and product candidates that are important to the development and implementation of our business. We also rely on trade secrets and know-how relating to our proprietary technology and product candidates, continuing innovation and in-licensing opportunities to develop, strengthen and maintain our proprietary position in the field of cell and gene therapy. We additionally plan to rely on data exclusivity, market exclusivity and patent‐term extensions, when available, and, as appropriate, have sought and in the future may seek again and rely on regulatory protection afforded through Orphan Drug designations. Our commercial success may depend in part on our ability to obtain and maintain patent and other proprietary protection for our technology, inventions and improvements; to preserve the confidentiality of our trade secrets; to maintain our licenses to use intellectual property owned by third parties; to defend and enforce our proprietary rights, including our patents; and to operate without infringing on the valid and enforceable patents and other proprietary rights of third parties.

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We have in-licensed and procured, and filed for numerous patent applications, which include claims directed to compositions, methods of use, processes, dosing and formulations, and possess substantial know-how and trade secrets relating to the development and commercialization of our cell engineering technology platforms and related product candidates, including related manufacturing processes and protocols. Our intellectual property strategy is designed to provide multi-layered protection covering our product candidates, including ronde-cel, LYL273 and our next-generation solid tumor programs, as well as our various platform technologies and manufacturing protocols, including but not limited to c‐Jun, NR4A3, CD62L-positive cell enrichment, tumor restricted IL-12 variants and Epi‐R. For all patent applications, we determine claiming strategy on a case-by-case basis. We may file patent applications containing claims for protection of all useful applications of our proprietary technology platforms and any products, as well as new applications and/or uses we discover for existing technology platforms and products. We continuously reassess the number and type of patent applications, as well as the pending and issued patent claims, to ensure that maximum coverage and value are obtained for our processes and compositions. Further, claims may be modified during patent prosecution to meet our intellectual property and business needs. Notwithstanding these efforts, we cannot be sure that any patents will be granted with respect to any patent application we have licensed or filed or may license or file in the future, and we cannot be sure that any patents we have licensed or patents that may be licensed or granted to us in the future will not be challenged, invalidated or circumvented or that such patents will be commercially useful in protecting our technologies.

As of December 31, 2025, our patent portfolio consists of at least 45 issued patents and 150 pending patent applications that we either own or have licensed. Our portfolio covers our product candidates, including ronde-cel, LYL273 and our next-generation solid tumor programs, as well as various aspects of our technologies and manufacturing protocols, including but not limited to c-Jun, NR4A3, CD62L-positive cell enrichment, tumor restricted IL-12 variants and Epi‐R. The patents and patent applications in our portfolio are held primarily in the United States, Europe, Canada, Japan and Australia. For information related to our in-licensed intellectual property, see the subsection titled under “—License and Collaboration Agreements.”

Individual patents extend for varying periods of time, depending upon the date of filing of the patent application, the date of patent issuance and the legal term of patents in the countries in which they are obtained. Generally, patents issued for applications filed in the United States are effective for 20 years from the earliest nonprovisional filing date. In the United States, a patent’s term may be lengthened by patent term adjustment, which compensates a patentee for administrative delays by the U.S. Patent and Trademark Office (USPTO) in examining and granting a patent, or may be shortened if a patent is terminally disclaimed over an earlier filed patent. In addition, in certain instances, the patent term of a U.S. patent that covers an FDA‐approved drug may also be eligible for extension to recapture a portion of the term effectively lost as a result of clinical trials and the FDA regulatory review period. Such an extension is referred to as patent term extension. The restoration period cannot be longer than five years and the total patent term, including the restoration period, must not exceed 14 years following FDA approval. Similar provisions are available in Europe and certain other foreign jurisdictions to extend the term of a patent that covers an approved drug. However, there is no guarantee that the applicable authorities, including the FDA in the United States, will agree with our assessment of whether such extensions should be granted, and if granted, the length of such extensions. The duration of patents outside of the United States varies in accordance with provisions of applicable local law, but typically is also 20 years from the earliest nonprovisional filing date. The actual protection afforded by a patent varies on a product-by-product basis, from country-to-country, and depends upon many factors, including the type of patent, the scope of its coverage, the availability of regulatory-related extensions, the availability of legal remedies in a particular country and the validity and enforceability of the patent.

We may also rely, in some circumstances, on trade secrets to protect our technology. However, trade secrets are difficult to protect. We seek to protect our technology and product candidates, in part, by entering into confidentiality agreements with those who have access to our confidential information, including our employees, contractors, consultants, collaborators and advisors. We also seek to preserve the integrity and confidentiality of our proprietary technology and processes by maintaining physical security of our premises and physical and electronic security of our information technology systems. Although we have confidence in these individuals, organizations and systems, agreements or security measures may be breached and we may not have adequate remedies for any breach. In addition, our trade secrets may otherwise become known or may be independently discovered by competitors. To the extent that our employees, contractors, consultants, collaborators and advisors use intellectual property owned by others in their work for us, disputes may arise as to the rights in related or resulting know-how and inventions. For this and more comprehensive risks related to our proprietary technology, inventions, improvements and product candidates, see the subsection titled “Risk Factors —Risks Relating to Our Intellectual Property.”

Sales and Marketing

Given our stage of development, we have not yet established a commercial organization or distribution capabilities. We intend to either build a commercial infrastructure to support sales of any approved products or outsource some or all of this function to third parties. We intend to evaluate opportunities to work with partners that enhance our

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capabilities with respect to the development and commercialization of ronde-cel, LYL273, and any other product candidates we may develop. In addition, we intend to commercialize our product candidates, if approved, in key markets either alone or with partners to maximize the worldwide commercial potential of our programs for ronde‐cel and LYL273.

Government Regulation

The FDA and other regulatory authorities at federal, state and local levels, as well as in foreign countries, extensively regulate, among other things, the research, development, testing, manufacture, quality control, import, export, safety, effectiveness, labeling, packaging, storage, distribution, record keeping, approval, advertising, promotion, marketing, post-approval monitoring and post-approval reporting of biologics such as those we are developing. We, along with our third-party contractors, will be required to navigate the various nonclinical, clinical and commercial approval requirements of the governing regulatory agencies of the countries in which we wish to conduct trials or seek approval or licensure of our product candidates. The process of obtaining regulatory approvals and the subsequent compliance with applicable federal, state, local and foreign statutes and regulations require the expenditure of substantial time and financial resources.

U.S. Biologics Regulation

In the United States, biological products are subject to regulation under the Federal Food, Drug, and Cosmetic Act, the Public Health Service Act and other federal, state, local and foreign statutes and regulations. The process required by the FDA before biologics may be marketed in the United States generally involves the following:

•completion of nonclinical laboratory tests and animal studies performed in accordance with the FDA’s Good Laboratory Practice requirements (GLP);

•submission to the FDA of an IND application, which must become effective before human clinical trials may begin;

•approval by an Institutional Review Board (IRB) or ethics committee at each clinical site before the trial is commenced;

•performance of adequate and well-controlled human clinical trials according to the FDA’s regulations (commonly referred to as GCPs) and any additional requirements for the protection of human research subjects and their health information to establish the safety, purity and potency of the proposed biologic product candidate for its intended purpose;

•preparation of and submission to the FDA of a Biologics License Application (BLA), after completion of all pivotal clinical trials;

•a determination by the FDA within 60 days of its receipt of a BLA to file the application for review;

•satisfactory completion of an FDA pre-approval inspection of the manufacturing facility or facilities at which the proposed product is produced to assess compliance with cGMP and to assure that the facilities, methods and controls are adequate to preserve the biological product’s continued safety, purity and potency and, if applicable, to assess compliance with the FDA’s current Good Tissue Practices (cGTPs) requirements for the use of human cellular and tissue products, and of selected clinical investigation sites to assess compliance with GCPs;

•satisfactory completion of an FDA Advisory Committee review, if applicable;

•potential FDA audit of the nonclinical and clinical trial sites that generated the data in support of the BLA; and

•FDA review and approval of the BLA to permit commercial marketing of the product for particular indications for use in the United States.

An IND automatically becomes effective 30 days after receipt by the FDA, unless the FDA, within the 30-day time period, raises safety concerns or questions about the proposed clinical trial. In such a case, the IND may be placed on clinical hold and the IND sponsor and the FDA must resolve any outstanding concerns or questions before the clinical trial can begin. Submission of an IND, therefore, may or may not result in FDA authorization to begin a clinical trial. A clinical hold can additionally be imposed by the FDA at any time during the conduct of a clinical trial under an IND.

In addition to the submission of an IND to the FDA before initiation of a clinical trial in the United States, certain human clinical trials involving recombinant or synthetic nucleic acid molecules are subject to oversight of an Institutional Biosafety Committee (IBC) as set forth in the National Institutes of Health (NIH) Guidelines for Research Involving Recombinant DNA Molecules (the NIH Guidelines). Specifically, under the NIH Guidelines, supervision of human gene transfer trials includes evaluation and assessment by an IBC, a local institutional committee that reviews and oversees research utilizing recombinant or synthetic nucleic acid molecules at that institution. The IBC assesses the safety of the

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research and identifies any potential risk to public health or the environment, and such review may result in some delay before initiation of a clinical trial. While the NIH Guidelines are not mandatory unless the research in question is being conducted at or sponsored by institutions receiving NIH funding of recombinant or synthetic nucleic acid molecule research, many companies and other institutions not otherwise subject to the NIH Guidelines voluntarily follow them.

Clinical trials involve the administration of the investigational product to human subjects under the supervision of qualified investigators in accordance with GCPs, 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 trial, the parameters to be used in monitoring safety and the effectiveness criteria to be evaluated. A separate submission to the existing IND must be made for each successive clinical trial conducted during product development and for any subsequent protocol amendments. Furthermore, an IRB for each site proposing to conduct the clinical trial must review and approve the plan for any clinical trial and its informed consent form before the clinical trial begins at that site, and must monitor the trial until completed. Regulatory authorities, the IRB or the sponsor may suspend a clinical trial at any time on various grounds, including a finding that the subjects are being exposed to an unacceptable health risk or that the trial is unlikely to meet its stated objectives. Some trials also include oversight by an independent group of qualified experts organized by the clinical trial sponsor, known as a Data Safety Monitoring Committee, which provides authorization for whether or not a trial may move forward at designated checkpoints based on access to certain data from the trial and may halt the clinical trial if it determines that there is an unacceptable safety risk for subjects or other grounds, such as no demonstration of efficacy. There are also requirements governing the reporting of ongoing clinical trials and clinical trial results to public registries.

In some cases, the FDA may require, or companies may voluntarily pursue, additional clinical trials after a product is approved to gain more information about the product in the intended therapeutic indication, particularly for long‐term safety follow-up. These so-called Phase 4 trials may also be made a condition to approval of the BLA.

Concurrent with clinical trials, companies may complete additional animal studies and develop additional information about the biological characteristics of the product candidate and must finalize a process for manufacturing the product in commercial quantities in accordance with cGMP requirements. The manufacturing process must be capable of consistently producing quality batches of the product candidate and, among other things, must develop methods for testing the identity, strength, quality and purity of the final product. Additionally, appropriate packaging must be selected and tested, and stability studies must be conducted to demonstrate that the product candidate does not undergo unacceptable deterioration over its shelf life.

BLA Submission and Review by the FDA

Assuming successful completion of all required testing in accordance with all applicable regulatory requirements, the results of product development, nonclinical studies and clinical trials are submitted to the FDA as part of a BLA requesting approval to market the product for one or more indications. The BLA must include all relevant data available from nonclinical and clinical trials, including negative or ambiguous results, as well as positive findings, together with detailed information relating to the product’s chemistry, manufacturing, controls and proposed labeling, among other things. Data can come from company-sponsored clinical trials intended to test the safety and effectiveness of a use of the product, or from a number of alternative sources, including trials initiated by independent investigators. The submission of a BLA requires payment of a substantial application user fee to the FDA, unless a waiver or exemption applies.

Within 60 days following submission of the application, the FDA reviews a BLA to determine if it is substantially complete before the FDA accepts it for filing. The FDA may refuse to file any BLA that it deems incomplete or not properly reviewable at the time of submission and may request additional information. In this event, the BLA must be resubmitted with the additional information. Once a BLA has been accepted for filing, the FDA’s goal is to review standard applications within 10 months after the filing date, or, if the application qualifies for priority review, six months after the FDA accepts the application for filing. In both standard and priority reviews, the review process may also be extended by FDA requests for additional information or clarification. The FDA reviews a BLA to determine, among other things, whether a product is safe, pure and potent, and the facility in which it is manufactured, processed, packed or held meets standards designed to assure the product’s continued safety, purity and potency. The FDA may also convene an advisory committee to provide clinical insight on application review questions. The FDA is not bound by the recommendations of an advisory committee, but it may consider such recommendations carefully when making decisions.

Before approving a BLA, the FDA will typically inspect the facility or facilities where the product is manufactured. The FDA will not approve an application unless it determines that the manufacturing processes and facilities are in compliance with cGMP and adequate to assure consistent production of the product within required specifications. For a product candidate that is also a human cellular or tissue product, the FDA also will not approve the application if the manufacturer is not in compliance with cGTPs. These are FDA regulations that govern the methods used in, and the facilities and controls used for, the manufacture of human cells, tissues and cellular and tissue-based products (HCT/Ps),

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which are human cells or tissue intended for implantation, transplant, infusion or transfer into a human recipient. The primary intent of the GTP requirements is to ensure that cell and tissue-based products are manufactured in a manner designed to prevent the introduction, transmission and spread of communicable disease. FDA regulations also require tissue establishments to register and list their HCT/Ps with the FDA and, when applicable, to evaluate donors through screening and testing. Additionally, before approving a BLA, the FDA will typically inspect one or more clinical sites to assure compliance with GCP. If the FDA determines that the application, manufacturing process or manufacturing facilities, or data collected from clinical trial sites are not acceptable, it will outline the deficiencies in the submission and often will request additional testing or information. Notwithstanding the submission of any requested additional information, the FDA ultimately may decide that the application does not satisfy the regulatory criteria for approval.

After the FDA evaluates a BLA and conducts inspections of manufacturing facilities where the investigational product and/or its drug substance will be produced, the FDA may issue an approval letter or a Complete Response Letter (CRL). An approval letter authorizes commercial marketing of the product with specific prescribing information for specific indications. A CRL describes all of the deficiencies that the FDA has identified in the BLA, except that where the FDA determines that the data supporting the application are inadequate to support approval, the FDA may issue the CRL without first conducting required inspections, testing submitted product lots and/or reviewing proposed labeling. In issuing the CRL, the FDA may recommend actions that the applicant might take to place the BLA in condition for approval, including requests for additional information or clarification. The FDA may delay or refuse approval of a BLA if applicable regulatory criteria are not satisfied, require additional testing or information and/or require post-marketing testing and surveillance to monitor the safety or efficacy of a product.

If regulatory approval of a product is granted, such approval will be granted for particular indications and may entail limitations on the indicated uses for which such product may be marketed. For example, the FDA may approve the BLA with a Risk Evaluation and Mitigation Strategy (REMS), to ensure the benefits of the product outweigh its risks, or otherwise limit the scope of any approval. A REMS is a safety strategy implemented to manage a known or potential serious risk associated with a product and to enable patients to have continued access to such medicines by managing their safe use, and could include medication guides, physician communication plans or elements to assure safe use, such as restricted distribution methods, patient registries and other risk minimization tools. The FDA also may condition approval on, among other things, changes to proposed labeling or the development of adequate controls and specifications. Once approved, the FDA may withdraw the product approval if compliance with pre- and post-marketing requirements is not maintained or if problems occur after the product reaches the marketplace. The FDA may require one or more Phase 4 post-marketing trials and surveillance to further assess and monitor the product’s safety and effectiveness after commercialization and may limit further marketing of the product based on the results of these post-marketing trials.

Expedited Development and Review Programs

The FDA offers a number of expedited development and review programs for qualifying product candidates. For example, the Fast Track program is intended to expedite or facilitate the process for reviewing new products that are intended to treat a serious or life-threatening disease or condition and demonstrate the potential to address unmet medical needs for the disease or condition. Specifically, new biological products are eligible for Fast Track designation if they are intended to treat a serious or life-threatening disease or condition and demonstrate the potential to address unmet medical needs for the disease or condition. Fast Track designation applies to the combination of the product and the specific indication for which it is being studied. The sponsor of a new biologic may request that the FDA designate the biologic as a Fast Track product at any time during the clinical development of the product. The sponsor of a Fast Track product has opportunities for more frequent interactions with the applicable FDA review team during product development and, once a BLA is submitted, the product candidate may be eligible for priority review. A Fast Track product may also be eligible for rolling review, where the FDA may consider for review sections of the BLA on a rolling basis before the complete application is submitted, if the sponsor provides a schedule for the submission of the sections of the BLA, the FDA agrees to accept sections of the BLA and determines that the schedule is acceptable, and the sponsor pays any required user fees upon submission of the first section of the BLA.

A product candidate intended to treat a serious or life-threatening disease or condition may also be eligible for Breakthrough Therapy Designation to expedite its development and review. A product candidate can receive Breakthrough Therapy Designation if preliminary clinical evidence indicates that the product candidate, alone or in combination with one or more other drugs or biologics, 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 includes all of the Fast Track program features, as well as more intensive FDA interaction and guidance beginning as early as Phase 1 and an organizational commitment to expedite the development and review of the product candidate, including involvement of senior managers.

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Any marketing application for a drug or biologic submitted to the FDA for approval, including a product candidate with Fast Track and/or Breakthrough Therapy Designation, may be eligible for other types of FDA programs intended to expedite development and review, such as Priority Review and Accelerated Approval. A product candidate is eligible for Priority Review if it has the potential to provide safe and effective therapy where no satisfactory alternative therapy exists or a significant improvement in the treatment, diagnosis or prevention of a disease compared to marketed products. The FDA will attempt to direct additional resources to the evaluation of an application for a new biological product designated for Priority Review in an effort to facilitate the review. For original BLAs, Priority Review designation means the FDA’s goal is to take action on the marketing application within six months of the 60-day filing date (as compared to 10 months under standard review).

Additionally, product candidates studied for their safety and effectiveness in treating serious or life-threatening diseases or conditions may receive Accelerated Approval upon a determination that the product has an effect on 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. As a condition of Accelerated Approval, the FDA will generally require the sponsor to perform adequate and well-controlled post-marketing clinical trials to verify and describe the anticipated effect on irreversible morbidity or mortality or other clinical benefit. Products receiving Accelerated Approval may be subject to expedited withdrawal procedures if the sponsor fails to conduct the required post-marketing studies or if such studies fail to verify the predicted clinical benefit. In addition, the FDA currently requires as a condition for Accelerated Approval pre-approval of promotional materials, which could adversely impact the timing of the commercial launch of the product.

Regenerative Medicine Advanced Therapy (RMAT) designation is intended to facilitate an efficient development program for, and expedite review of, any drug or biologic that meets the following criteria: (i) the drug or biologic qualifies as a RMAT, which is defined as a cell therapy, therapeutic tissue engineering product, human cell and tissue product, or any combination product using such therapies or products, with limited exceptions; (ii) the drug or biologic is intended to treat, modify, reverse or cure a serious or life-threatening disease or condition; and (iii) preliminary clinical evidence indicates that the drug or biologic has the potential to address unmet medical needs for such a disease or condition. RMAT designation provides all the benefits of Breakthrough Therapy Designation, including more frequent meetings with the FDA to discuss the development plan for the product candidate and eligibility for rolling review and Priority Review. Product candidates granted RMAT designation may also be eligible for Accelerated Approval on the basis of a surrogate or intermediate endpoint reasonably likely to predict long-term clinical benefit, or reliance upon data obtained from a meaningful number of clinical trial sites, including through expansion of trials to additional sites. RMAT-designated products that receive Accelerated Approval may, as appropriate, fulfill their post-approval requirements through submission of clinical evidence, clinical trials, patient registries or other sources of real-world evidence (such as electronic health records); through the collection of larger confirmatory data sets; or via post-approval monitoring of all patients treated with such therapy prior to approval of such therapy. Fast Track, Breakthrough Therapy Designation, Priority Review, Accelerated Approval and RMAT designation do not change the standards for approval but may expedite the development or approval process. Even if a product candidate qualifies for one or more of these programs, the FDA may later decide that the product candidate no longer meets the conditions for qualification or decide that the time period for FDA review or approval will not be shortened.

Orphan Drug Designation and Exclusivity

Under the Orphan Drug Act, the FDA may grant Orphan Drug Designation (ODD) to a drug or biologic intended to treat a rare disease or condition, defined as a disease or condition with a patient population of fewer than 200,000 individuals in the United States, or a patient population greater than 200,000 individuals in the United States and when there is no reasonable expectation that the cost of developing and making available the drug or biologic in the United States will be recovered from sales in the United States for that drug or biologic. ODD must be requested before submitting a BLA. After the FDA grants ODD, the generic identity of the therapeutic agent and its potential orphan use are disclosed publicly by the FDA. ODD does not convey any advantage in or shorten the duration of the regulatory review and approval process.

In the United States, ODD entitles a party to financial incentives such as opportunities for grant funding towards clinical trial costs, tax advantages and user-fee waivers. In addition, if a product that has ODD subsequently receives the first FDA approval for a particular drug or biologic for the disease for which it has such designation, the product is entitled to orphan product exclusivity, which means that the FDA may not approve any other applications, including a full BLA, to market the same biologic for the same indication for seven years, except in limited circumstances, such as a showing of clinical superiority to the product with orphan drug exclusivity or if the FDA finds that the holder of the orphan drug exclusivity has not shown that it can assure the availability of sufficient quantities of the orphan drug to meet the needs of patients with the disease or condition for which the drug was designated. Orphan drug exclusivity does not prevent the

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FDA from approving a different drug or biologic for the same disease or condition, or the same drug or biologic for a different disease or condition. Orphan product exclusivity also could block the approval of one of our products for seven years if a competitor obtains approval of the same biological product as defined by the FDA or if our product candidate is determined to be contained within the competitor’s product for the same indication or disease.

Post-Approval Requirements

Biologics are subject to pervasive and continuing regulation by the FDA, including, among other things, requirements relating to 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, annual program fees for any marketed products. Biologic manufacturers and other entities involved in the manufacture and distribution of approved biological products 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 requirements and other laws. Accordingly, manufacturers must continue to expend time, money and effort in the area of production and quality control to maintain cGMP compliance. Changes to the manufacturing process or facility 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. 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 adverse events 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‐marketing studies or clinical trials to assess new safety risks; or imposition of distribution restrictions or other restrictions under a REMS program. Other potential consequences include, among other things: restrictions on the marketing or manufacturing of the product, complete withdrawal of the product from the market or product recalls; fines, warning letters or untitled letters; clinical holds on clinical trials; refusal of the FDA to approve pending applications or supplements to approved applications, or suspension or revocation of product license approvals; product seizure or detention, or refusal to permit the import or export of products; consent decrees, corporate integrity agreements, debarment or exclusion from federal healthcare programs; mandated modification of promotional materials and labeling and the issuance of corrective information; the issuance of safety alerts, Dear Healthcare Provider letters, press releases and other communications containing warnings or other safety information about the product; or injunctions or the imposition of civil or criminal penalties.

The FDA closely regulates the marketing, labeling, advertising and promotion of biologics. A company can make only those 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. FDA sanctions could include refusal to approve pending applications, withdrawal of an approval, clinical hold, warning or untitled letters, product recalls, product seizures, total or partial suspension of production or distribution, injunctions, fines, refusals of government contracts, mandated corrective advertising or communications with doctors, debarment, restitution, disgorgement of profits or civil or 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 and approved by the FDA. Such off-label uses are common across medical specialties. Physicians may believe, in their independent medical judgment, that such off-label uses are the best treatment for many patients in varied circumstances. The FDA does not regulate the behavior of physicians in their choice of treatments. The FDA does, however, restrict sponsors’ communications on the subject of off-label use of their products.

Biosimilars and Reference Product Exclusivity

The Biologics Price Competition and Innovation Act (BPCIA) created an abbreviated approval pathway for biological products that are biosimilar to or interchangeable with an FDA-licensed reference biological product. The FDA has issued several guidance documents outlining an approach to review and approval of biosimilars.

Biosimilarity, which requires that there be no clinically meaningful differences between the biological product and the reference product in terms of safety, purity and potency, can be shown through analytical studies, animal studies and a clinical trial or trials. 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

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relative to exclusive use of the reference biologic. However, complexities associated with the larger, and often more complex, structures of biological products, as well as the processes by which such products are manufactured, pose significant hurdles to implementation of the abbreviated approval pathway that are still being worked out by the FDA.

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 twelve (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 nonclinical data and data from adequate and well-controlled clinical trials to demonstrate the safety, purity and potency of its product. The BPCIA also created certain exclusivity periods for biosimilars approved as interchangeable products.

A biological product can also obtain pediatric market exclusivity in the United States. Pediatric exclusivity, if granted, adds six months to existing exclusivity periods and patent terms. This six-month exclusivity, which runs from the end of other exclusivity protection or patent term, may be granted based on the voluntary completion of a pediatric study in accordance with an FDA-issued “Written Request” for such a study. 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 and implementation of the BPCIA is subject to significant uncertainty.

Government Regulation Outside of the United States

In addition to regulations in the United States, we may be subject to a variety of regulations in other jurisdictions governing, among other things, clinical trials and any commercial sales and distribution of our products. Because biologically sourced raw materials are subject to unique contamination risks, their use may be restricted in some countries. Whether or not we obtain FDA approval for a product, we must obtain the requisite approvals from regulatory authorities in foreign countries prior to the commencement of clinical trials or marketing of the product in those countries. Certain countries outside of the United States have a similar process that requires the submission of a clinical trial application much like the IND prior to the commencement of human clinical trials.

The requirements and process governing the conduct of clinical trials, product licensing, pricing and reimbursement vary from country to country. In all cases, clinical trials must be conducted in accordance with GCP, applicable regulatory requirements and the ethical principles that have their origin in the Declaration of Helsinki.

Applications for marketing approval in the EU and other countries must also follow detailed laws and procedures that vary from those in the US.

Moreover, in countries outside of the U.S., including the EU and countries in Eastern Europe, Latin America or Asia, the requirements governing product licensing, pricing and reimbursement vary from country to country.

If we fail to comply with applicable foreign regulatory requirements, we may be subject to, among other things, fines, suspension or withdrawal of regulatory approvals, product recalls, seizure of products, operating restrictions and criminal prosecution.

Other Laws

Pharmaceutical companies are subject to additional healthcare regulation and enforcement by the federal government and by authorities in the states and foreign jurisdictions in which they conduct their business and may constrain the financial arrangements and relationships through which we research, sell, market and distribute any products for which we obtain marketing approval. Such laws include, without limitation, the U.S. Foreign Corrupt Practices Act of 1977 (FCPA), federal and state anti-kickback, fraud and abuse, false claims, data privacy and security, price reporting and physician and other health care provider transparency laws and regulations

The FCPA prohibits any U.S. individual or business from paying, offering, or authorizing payment or offering of anything of value, directly or indirectly, to any foreign official, political party or candidate for the purpose of influencing any act or decision of the foreign entity in order to assist the individual or business in obtaining or retaining business. The FCPA also obligates companies whose securities are listed in the United States to comply with accounting provisions requiring us to maintain books and records that accurately and fairly reflect all transactions of the corporation, including international subsidiaries, and to devise and maintain an adequate system of internal accounting controls for international operations.

The federal Anti-Kickback Statute prohibits, among other things, any person or entity, from knowingly and willfully offering, paying, soliciting or receiving any remuneration, directly or indirectly, overtly or covertly, in cash or in

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kind, to induce or in return for purchasing, leasing, ordering or arranging for the purchase, lease or order of any item or service reimbursable under Medicare, Medicaid or other federal healthcare programs.

The federal False Claims Act (FCA) prohibits, among other things, any person or entity from knowingly presenting, or causing to be presented, a false claim for payment to, or approval by, the federal government or knowingly making, using or causing to be made or used a false record or statement material to a false or fraudulent claim to the federal government.

The federal Health Insurance Portability and Accountability Act of 1996, as amended by the Health Information Technology for Economic and Clinical Health Act (HITECH) (as amended, HIPAA), also created federal criminal statutes that prohibit knowingly and willfully executing, or attempting to execute, a scheme to defraud or to obtain, by means of false or fraudulent pretenses, representations or promises, any money or property owned by, or under the control or custody of, any healthcare benefit program, including private third-party payors and knowingly and willfully falsifying, concealing or covering up by trick, scheme or device, a material fact or making any materially false, fictitious or fraudulent statement in connection with the delivery of or payment for healthcare benefits, items or services.

Additionally, the federal Physician Payments Sunshine Act, and its implementing regulations, require that certain manufacturers of commercial drugs, devices, biological and medical supplies for which payment is available under Medicare, Medicaid or the Children’s Health Insurance Program (with certain exceptions) annually report information related to certain payments or other transfers of value made or distributed to physicians (defined to include doctors, dentists, optometrists, podiatrists and chiropractors), other health care professionals (such as physician assistants and nurse practitioners) and teaching hospitals and certain ownership and investment interests held by these physicians and their immediate family members.

We may also be subject to data privacy and security regulations by both the federal government and the states in which we conduct our business. HIPAA imposes requirements on covered entities, including certain healthcare providers, health plans, healthcare clearinghouses and their respective business associates that create, receive, maintain or transmit individually identifiable health information for or on behalf of a covered entity as well as their covered subcontractors relating to the privacy, security and transmission of individually identifiable health information.

We may also be subject to foreign and state law equivalents of each of the federal laws described above, such as anti-kickback and false claims laws which may apply to items or services reimbursed by state health insurance programs or any third-party payor, including commercial insurers. Further, in order to distribute products commercially, we must comply with state laws that require the registration of manufacturers and wholesale distributors of pharmaceutical products in a state, including, in certain states, manufacturers and distributors who ship products into the state even if such manufacturers or distributors have no place of business within the state. Some states also impose requirements on manufacturers and distributors to establish the pedigree of product in the chain of distribution, including some states that require manufacturers and others to adopt new technology capable of tracking and tracing product as it moves through the distribution chain. Several states have enacted legislation requiring pharmaceutical companies to establish marketing compliance programs, file periodic reports with the state, make periodic public disclosures on sales, marketing, pricing, track and report gifts, compensation and other remuneration made to physicians and other healthcare providers, clinical trials and other activities, and/or register their sales representatives, as well as to prohibit pharmacies and other healthcare entities from providing certain physician prescribing data to pharmaceutical companies for use in sales and marketing, and to prohibit certain other sales and marketing practices. All of our activities are potentially subject to federal and state consumer protection and unfair competition laws.

If our operations are found to be in violation of any of the healthcare laws described above or any other federal, state or foreign laws or governmental regulations that apply to us, we may be subject to significant penalties, including without limitation, civil, criminal and/or administrative penalties, damages, fines, disgorgement, imprisonment, exclusion from participation in government programs, such as Medicare and Medicaid, injunctions, private “qui tam” actions brought by individual whistleblowers in the name of the government, integrity oversight and reporting obligations or refusal to allow us to enter into government contracts, contractual damages, reputational harm, administrative burdens, diminished profits and future earnings, and the curtailment or restructuring of our operations, any of which could adversely affect our ability to operate our business and our results of operations.

Coverage and Reimbursement

Sales of any product depend, in part, on the extent to which such product will be covered by third-party payors, such as federal, state and foreign government healthcare programs, commercial insurance and managed healthcare organizations, and the level of reimbursement for such product by third-party payors. Decisions regarding the extent of coverage and amount of reimbursement to be provided are made on a plan-by-plan basis. Reimbursement by a third-party payor may depend upon a number of factors, including the third-party payor’s determination that a product is safe,

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effective and medically necessary; appropriate for the specific patient; cost-effective; supported by peer-reviewed medical journals; included in clinical practice guidelines; and neither cosmetic, experimental, nor investigational. A third-party payor could also require that certain lines of therapy be completed or failed prior to reimbursing our therapy. The principal decisions about reimbursement for new medicines are typically made by the Centers for Medicare & Medicaid Services (CMS), an agency within the U.S. Department of Health and Human Services (HHS). CMS decides whether and to what extent products will be covered and reimbursed under Medicare and private payors tend to follow CMS to a substantial degree. Third-party payors determine which products and procedures they will cover and establish reimbursement levels. Even if a third-party payor covers a particular product or procedure, the resulting reimbursement payment rates may not be adequate. Additionally, any companion diagnostic tests developed for use with a product are required to obtain coverage and reimbursement for those tests separate and apart from the coverage and reimbursement sought for such product. These third-party payors are increasingly reducing coverage and reimbursement for medical products, drugs and services. In addition, the U.S. government, state legislatures and foreign governments have continued implementing cost-containment programs, including price controls, restrictions on coverage and reimbursement and requirements for substitution of generic products. Adoption of price controls and cost-containment measures, and adoption of more restrictive policies in jurisdictions with existing controls and measures, could further limit sales of any product. Decreases in third-party reimbursement for any product or a decision by a third-party payor not to cover a product could reduce physician usage and patient demand for the product and also have a material adverse effect on sales.

Healthcare Reform

In the United States, in March 2010, the Patient Protection and Affordable Care Act of 2010, as amended by the Health Care and Education Reconciliation Act of 2010 (collectively, the ACA), was enacted, which substantially changed the way healthcare is financed by both governmental and private insurers, and continues to impact the pharmaceutical industry.

There have been executive, judicial and Congressional challenges and amendments to certain aspects of the ACA. On July 4, 2025, the One Big Beautiful Bill Act (the OBBBA) was signed into law, which narrowed access to ACA marketplace exchange enrollment and declined to extend the ACA enhanced advanced premium tax credits that expired at the end of 2025, which, among other provisions in the law, are anticipated to reduce the number of Americans with health insurance. The OBBBA also is expected to reduce Medicaid spending and enrollment by implementing work requirements for some beneficiaries, capping state-directed payments, reducing federal funding and limiting provider taxes used to fund the program. Congress is considering proposed legislation intended to further reduce healthcare costs with alternatives to replace the expired ACA subsidies. It is possible that the ACA will be subject to additional challenges in the future.

Other legislative changes have also been proposed and adopted in the United States since the ACA was enacted. On August 2, 2011, the Budget Control Act of 2011, among other things, included aggregate reductions to Medicare payments to providers of 2% per fiscal year, which began in 2013 and will remain in effect through 2032.

There has been heightened governmental scrutiny recently over the manner in which pharmaceutical companies set prices for their marketed products, which has resulted in several Congressional inquiries and proposed federal legislation, as well as state efforts, designed to, among other things, bring more transparency to product pricing, reduce the cost of prescription drugs under Medicare, review the relationship between pricing and manufacturer patient programs, and reform government program reimbursement methodologies for drug products.

The current administration is pursuing policies to reduce regulations and expenditures across government agencies including at HHS, the FDA, CMS and related agencies. Recent actions include (1) directing agencies to reduce agency workforce and cut programs; (2) directing HHS and other agencies to lower prescription drug costs through a variety of initiatives, including by improving upon the Medicare Drug Price Negotiation Program and establishing Most-Favored-Nation pricing for pharmaceutical products; (3) imposing tariffs on imported pharmaceutical products; and (4) as part of the Make America Healthy Again (MAHA) Commission’s Strategy Report released in September 2025, working across government agencies to increase enforcement on direct-to-consumer pharmaceutical advertising. These actions and policies may significantly reduce U.S. drug prices, potentially impacting manufacturers’ global pricing strategies and profitability, while increasing their operational costs and compliance risks. In June 2024, the U.S. Supreme Court’s Loper Bright decision greatly reduced judicial deference to regulatory agencies, which could increase successful legal challenges to federal regulations affecting our operations. Congress may introduce and ultimately pass health care related legislation that could impact the drug approval process.

At the state level, legislatures have increasingly passed legislation and implemented regulations designed to control pharmaceutical and biological product pricing, including price or patient reimbursement constraints, discounts, restrictions on certain product access and marketing cost disclosure and transparency measures, and, in some cases, designed to encourage importation from other countries and bulk purchasing.

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These health reform measures will result in additional downward pressure on coverage and the price that we receive for any approved product and could seriously harm our business. Any reduction in reimbursement from Medicare and other government programs may result in a similar reduction in payments from private payors. The implementation of cost containment measures or other healthcare reforms may prevent us from being able to generate revenue, attain profitability or commercialize our products (if approved). In addition, it is possible that there will be further legislation or regulation that could harm our business, financial condition and results of operations.

Other Data Privacy and Security Laws

In the ordinary course of our business, we process or receive personal or sensitive data. We are, or may become, subject to numerous data privacy and security obligations, including federal, state, local and foreign laws, regulations, guidance and industry standards related to data privacy and security in the jurisdictions in which we are established or in which we sell or market any approved products or run clinical trials. Such laws may include those from, without limitation, the Federal Trade Commission Act, the California Consumer Privacy Act of 2018, as amended by the California Privacy Rights Act of 2020 (CPRA) (collectively, CCPA), the EU’s General Data Protection Regulation 2016/679 (EU GDPR), the EU GDPR as it forms part of UK law by virtue of section 3 of the European Union (Withdrawal) Act 2018 (UK GDPR) and the ePrivacy Directive. Several states within the United States have also enacted or proposed comprehensive data privacy and security laws. Additionally, we are, or may become, subject to various U.S. federal and state consumer protection laws, which require us to publish statements that accurately and fairly describe how we handle personal data and choices individuals may have about the way we handle their personal data.

The CCPA, CPRA and EU GDPR are examples of the increasingly stringent and evolving regulatory frameworks related to personal data processing that may increase our compliance obligations and exposure for any noncompliance. For example, the CCPA imposes obligations on covered businesses to provide specific disclosures related to a business’ collecting, using and disclosing personal data and to honor certain requests from California residents related to their personal data. Also, the CCPA provides for civil penalties and a private right of action for data breaches that may include an award of statutory damages.

Foreign data privacy and security laws (including but not limited to the EU GDPR and UK GDPR) impose significant and complex compliance obligations on entities that are subject to those laws. As one example, the EU GDPR applies to any company established in the European Economic Area (EEA) and to companies established outside the EEA that process personal data in connection with the offering of goods or services to data subjects in the EEA or the monitoring of the behavior of data subjects in the EEA. Under the GDPR, companies may face temporary or definitive bans on data processing and other corrective actions; fines of up to 20 million Euros under the EU GDPR; 17.5 million pounds sterling under the UK GDPR or, in each case, 4% of the annual global revenue, whichever is greater; or private litigation related to processing of personal data brought by classes of data subjects or consumer protection organizations authorized at law to represent their interests.

See the section titled “Risks Related to Our Business and Industry” for additional information about the laws and regulations to which we may become subject and about the risks to our business associated with such laws and regulations.

Employees and Human Capital Management

Our Mission

We are a late-stage clinical cell therapy company advancing a pipeline of proprietary next-generation autologous CAR T-cell product candidates for patients with cancer. Our goal is to fully realize the curative potential of cell therapy for patients with hematologic malignancies and solid tumors. We strive to create an environment where everyone can do their best work, be themselves, and thrive personally and professionally. Our culture is grounded by innovative science and a passion to identify and deliver better therapies for patients. The needs of patients drive our sense of urgency to achieve our important mission.

Our Values

We believe success comes when we align our core values with our mission; this gives us focus and direction in how we do our work. Our core values are:

•Science: We value evidence over opinion and we focus and execute on the critical efforts that matter most.

•Courage: We challenge the status quo – we are bold and willing to think and act differently.

•Respect: We operate with positive intent and seek to understand and communicate directly, transparently and honestly.

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•Collaboration: We work together to create value, working across teams to solve our most challenging problems to continually improve and learn.

Our values are further defined as specific ways of working that are embedded in our performance management processes. Our ways of working, or the Lyell Behaviors, exemplify our values as well as principles of patient-centricity, innovation and inclusion. High performers at Lyell not only achieve their goals, but consistently and effectively demonstrate the Lyell Behaviors.

Our Employees

Our people drive our mission. We compete in the highly competitive biotechnology industry; attracting, retaining and developing a diverse group of talented employees is crucial to our strategy and we believe is a competitive advantage. What sets Lyell apart from our peers is the breadth of work we do; from discovery research to drug development and manufacturing, we are a high-performing team across our many functions. Lyell provides the opportunity to see first-hand how cell therapy is brought to life and gives employees opportunities to engage and make meaningful contributions. The labor market continues to reflect a limited pool of skilled individuals with substantial experience discovering, developing and manufacturing cell therapy medicines. As we plan for commercialization, this level of competition will continue to be a challenge, and we will continue to compete for talent against businesses that are much larger and more heavily resourced.

LYEL US Equity

LYEL · 10-K · period ended 2025-12-31

Item 1. Business.

LYEL US Equity☆

LYEL · 10-K · period ended 2025-12-31

Item 1. Business.

LYEL US Equity