nrix-20251130

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 November 30, 2025

Commission File Number 001-39398

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NURIX THERAPEUTICS, INC.

(Exact name of Registrant as specified in its Charter)

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(Address of principal executive offices) (Zip Code)

Registrant’s telephone number, including area code: (415) 660-5320

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

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

Common Stock, par value $0.001 per share NRIX Nasdaq Global 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. Yesx No o

Indicate by check mark if the Registrant is not required to file reports pursuant to Section 13 or 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, 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 x Accelerated filer o

Non-accelerated filer o Smaller reporting company o

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

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 Exchange Act). Yes o No x

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. x

The aggregate market value of the common stock held by non-affiliates of the Registrant, based on the closing price of the Registrant’s common stock on May 30, 2025 (the last business day of the Registrant’s most recently completed second fiscal quarter) as reported by the Nasdaq Global Market on such date was approximately $807.5 million. This calculation does not reflect a determination that certain persons are affiliates of the Registrant for any other purpose.

As of January 23, 2026, the Registrant had 102,843,012 shares of common stock, $0.001 par value per share, outstanding.

DOCUMENTS INCORPORATED BY REFERENCE

Certain sections of the Registrant’s definitive Proxy Statement to be filed in connection with the Registrant’s 2026 Annual Meeting of Stockholders are incorporated by reference into Part III of this Annual Report on Form 10-K where indicated. Such definitive Proxy Statement will be filed with the Securities and Exchange Commission pursuant to Regulation 14A within 120 days of the Registrant’s fiscal year ended November 30, 2025.

TABLE OF CONTENTS

Page

PART I

Item 1. Business 4

Item 1A. Risk Factors 50

Item 1B. Unresolved Staff Comments 107

Item 1C. Cybersecurity 108

Item 2. Properties 109

Item 3. Legal Proceedings 109

Item 4. Mine Safety Disclosures 109

PART II

Item 6. [Reserved] 111

Item 7A. Quantitative and Qualitative Disclosures About Market Risk 125

Item 8. Financial Statements and Supplementary Data 126

Item 9A. Controls and Procedures 159

Item 9B. Other Information 159

Item 9C. Disclosure Regarding Foreign Jurisdictions that Prevent Inspection 160

PART III

Item 10. Directors, Executive Officers and Corporate Governance 161

Item 11. Executive Compensation 161

Item 14. Principal Accounting Fees and Services 161

PART IV

Item 15. Exhibits and Financial Statement Schedules 162

SPECIAL NOTE REGARDING FORWARD-LOOKING STATEMENTS

This Annual Report on Form 10-K contains forward-looking statements within the meaning of the Private Securities Litigation Reform Act of 1995. All statements contained in this Annual Report on Form 10-K other than statements of historical fact, including statements concerning our business strategy and plans, future operating results and financial position, as well as our objectives and expectations for our future operations, are forward-looking statements.

In some cases, you can identify forward-looking statements by such terminology as “believe,” “may,” “will,” “potentially,” “estimate,” “continue,” “anticipate,” “intend,” “could,” “would,” “project,” “plan,” “expect” and similar expressions that convey uncertainty of future events or outcomes, although not all forward-looking statements contain these words. Forward-looking statements include, but are not limited to, statements about:

•the timing and conduct of our clinical trial programs for our lead drug candidates bexobrutideg (NX-5948), zelebrudomide (NX-2127) and NX-1607 and other drug candidates, including statements regarding the timing of data and anticipated announcements, the selection of new development candidates and the initiation of clinical trials;

•the timing of, and our ability to obtain, marketing approvals for our lead drug candidates bexobrutideg, zelebrudomide and NX-1607 and other drug candidates;

•our plans to pursue research and development of other drug candidates;

•the timing of investigational new drug application (IND) submissions for our drug candidates;

•the potential advantages of our DEL-AI platform, our drug candidates and degrader antibody conjugates (DACs);

•the extent to which our scientific approach, our DEL-AI platform, protein degradation, antibody-drug conjugation, and DACs may potentially address a broad range of diseases;

•the potential benefits of our arrangements with Gilead Sciences, Inc., Sanofi S.A. and Seagen Inc. (now a part of Pfizer Inc.);

•the timing of and our ability to obtain and maintain regulatory approvals for our drug candidates;

•the potential receipt of revenue from future sales of our drug candidates;

•the rate and degree of market acceptance and clinical utility of our drug candidates;

•our estimates regarding the potential market opportunity for our drug candidates;

•our sales, marketing and distribution capabilities and strategy;

•our ability to establish and maintain arrangements for the manufacturing of our drug candidates;

•the expected impact of global business, political and macroeconomic conditions, including inflation, interest rate fluctuations and volatile market conditions, changing tariff policies and trade restrictions, uncertainty with respect to the federal budget and debt ceiling and potential government shutdowns related thereto, cybersecurity events, instability in the global banking system, and global events, including regional conflicts around the world, on our business, clinical trials, financial condition, liquidity and results of operations;

•the potential achievement of milestones and receipt of royalty payments under our collaborations;

•our ability to enter into additional collaborations with third parties;

•our intellectual property position;

•our estimates regarding expenses, future revenues, capital requirements and needs for additional financing;

•the impact of government laws and regulations; and

•our competitive position.

We have based these forward-looking statements largely on our current expectations and projections about future events and trends that we believe may affect our business, financial condition, results of operations, prospects and financial needs. 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 in the section titled “Risk Factors” 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 the forward-looking statements. We disclaim any intention or obligation to publicly update or revise any forward-looking statements for any reason or to conform such statements to actual results or revised expectations, except as required by law.

RISK FACTOR SUMMARY

Our business is subject to a number of risks and uncertainties, including those risks discussed at-length below. These risks include, among others, the following:

•We have incurred significant losses since our inception. We expect to incur losses over at least the next several years and may never achieve or maintain profitability.

•We have never generated revenue from product sales and may never be profitable.

•We will need substantial additional funding. If we are unable to raise capital when needed, we may be required to delay, limit, reduce or terminate our research or product development programs or future commercialization efforts.

•Current and future legislation may increase the difficulty and cost for us, and any collaborators, to obtain marketing approval of and commercialize our drug candidates and affect the prices we, or they, may obtain.

•We are early in our development efforts. Our lead drug candidates, bexobrutideg, zelebrudomide and NX-1607, are in the early stages of clinical development. If we are unable to advance our drug candidates through clinical development, develop, obtain regulatory approval for and commercialize our drug candidates or experience significant delays in doing so, our business may be materially harmed.

•Our limited operating history may make it difficult to evaluate the success of our business to date and to assess our future viability.

•If serious adverse events, undesirable side effects or unexpected characteristics are identified during the development of any drug candidates we may develop, we may need to abandon or limit our further clinical development of those drug candidates.

•The results of preclinical studies and early-stage clinical trials may not be predictive of future results. Initial success in clinical trials may not be indicative of results obtained in later-stage trials or when these trials are completed.

•We have received Orphan Drug Designation for bexobrutideg and may seek Orphan Drug Designation for other drug candidates in the future. If we decide to seek Orphan Drug Designation or other designations from regulators for any of our current or future drug candidates, we may be unsuccessful or may be unable to maintain the benefits associated with these designations, including the potential for supplemental market exclusivity associated with an Orphan Drug Designation.

•If any of our drug candidates are not considered to be a new active substance or are deemed to fall within the “global marketing authorization” of an existing medicinal product or if pediatric studies are not adequately completed, such drug candidates may fail to obtain regulatory data protection or an extension to existing regulatory data protection.

•We face substantial competition in an environment of rapid technological change, which may result in others discovering, developing or commercializing products before or more successfully than we do.

•We expect to depend on collaborations with third parties for the research, development and commercialization of certain of the drug candidates we may develop. If any such collaborations are not successful, we may not be able to capitalize on the market potential of those drug candidates.

•We rely on third-party contract manufacturing organizations (CMOs) for the manufacture of both drug substance and finished drug product for our drug candidates for preclinical and clinical testing and expect to continue to do so for any future clinical trials and commercialization. This reliance on third parties may increase the risk that we will not have sufficient quantities of our drug candidates or products or such quantities at an acceptable cost or quality, which could delay, prevent or impair our development or commercialization efforts.

•If we are unable to obtain and maintain patent protection for our technology, our current drug candidates and any future drug candidates that we may develop, or if the scope of the patent protection obtained is not sufficiently broad, our competitors and other third parties could develop and commercialize technology and drug candidates similar or identical to ours, and our ability to successfully commercialize our technology and drug candidates may be impaired, and we may not be able to compete effectively in our market.

•We may not identify relevant third-party patents or may incorrectly interpret the relevance, scope or expiration of a third-party patent, and third parties may initiate legal proceedings alleging that we are infringing, misappropriating or otherwise violating their intellectual property rights, the outcome of which would be uncertain and could have a material adverse effect on our business.

•Unfavorable global economic conditions could adversely affect our business, financial condition, stock price and results of operations.

•If we fail to attract and retain management and other key personnel, we may be unable to continue to successfully develop our current and any future drug candidates, commercialize our drug candidates or otherwise implement our business plan.

•Even if we are able to commercialize any drug candidates, the products may become subject to unfavorable pricing regulations, third-party reimbursement practices or healthcare reform initiatives, or fail to secure a positive health technology assessment, which would harm our business.

PART I

Item 1. Business

When used in this report, unless otherwise indicated, “Nurix,” “Company,” “we,” “us” and “our” refers to Nurix Therapeutics, Inc. and its wholly owned subsidiaries.

Overview

We are a clinical stage biopharmaceutical company focused on the discovery, development and commercialization of targeted protein degradation medicines, the next frontier in innovative drug design aimed at improving treatment options for patients with cancer and inflammatory diseases. Powered by a fully artificial intelligence (AI)-integrated discovery engine capable of tackling any protein class, and coupled with leading ligase expertise, Nurix has built a significant advantage in translating the science of protein degradation into clinical advancements with the aim of establishing degrader-based treatments at the forefront of patient care. Our wholly owned, clinical stage pipeline includes three investigational drug candidates designed with the goal to be first-in-class or best-in-class therapeutics: bexobrutideg (NX-5948), a highly selective degrader of Bruton’s tyrosine kinase (BTK); zelebrudomide (NX-2127), a dual degrader of BTK and transcription factors IKZF1(Ikaros) and IKZF3 (Aiolos); and NX-1607, an inhibitor of Casitas B-lineage lymphoma proto-oncogene B (CBL-B), an E3 ligase that regulates activation of multiple immune cell types including T cells and NK cells. We are also advancing multiple potentially first-in-class or best-in-class degraders and degrader antibody conjugates (DACs) in our preclinical pipeline. Our partnered drug discovery pipeline consists of a clinical stage degrader of IRAK4 (NX-0479/GS-6791), a preclinical stage degrader of STAT6, currently in investigational new drug application (IND), enabling studies, and multiple currently undisclosed targets under collaboration agreements with Gilead Sciences, Inc. (Gilead), Sanofi S.A. (Sanofi) and Pfizer Inc. (Pfizer). Within these collaborations, we retain certain options for co-development, co-commercialization and profit sharing in the United States for multiple drug candidates. Both our wholly owned and partnered pipelines are driven by our DEL-AI discovery engine which employs advanced machine learning to enable all aspects of discovery, starting with DNA encoded library (DEL) hit-finding and degrader design, followed by automated chemistry synthesis and direct-to-biology screening and optimization, to rapidly generate degraders and DACs as new chemical entity drug candidates. By leveraging hundreds of billions of DEL compound binding signatures derived from thousands of DEL affinity screens collected from a diverse set of highly validated protein targets, our DEL-AI engine can prospectively identify binders as starting points for drug discovery for virtually any pharmaceutically relevant target.

Our Clinical and Preclinical Development Pipeline

Our wholly owned pipeline of drug candidates comprises three clinical stage oncology programs and multiple preclinical stage Targeted Protein Degrader (TPD) and Degrader Antibody Conjugate (DAC) programs spanning the therapeutic areas of oncology, inflammation and immunology. Our partnered pipeline further expands our reach into rheumatoid arthritis and Type 2 inflammation, as well as solid tumor oncology via multiple undisclosed programs. This combination of wholly owned and partnered portfolios across a range of indications and modalities demonstrates our ability to discover and advance novel medicines, many of which selectively target disease proteins previously thought to be undruggable. The following chart summarizes our clinical and preclinical pipelines and ongoing clinical studies:

Clinical Pipeline

Our portfolio of targeted protein degraders of the B‐cell signaling protein BTK comprises bexobrutideg, an investigational, orally bioavailable, highly selective BTK degrader for the treatment of relapsed or refractory B-cell malignancies and potentially autoimmune diseases, and zelebrudomide, an investigational, orally bioavailable degrader that simultaneously degrades BTK and two well-characterized cereblon neosubstrates IKZF1 (Ikaros) and IKZF3 (Aiolos) that are clinically validated transcription factor targets for relapsed or refractory B‐cell malignancies.

Status of Bexobrutideg: We are currently conducting a Phase 2 study of bexobrutideg in patients with relapsed or refractory CLL having failed three previous lines of therapy, specifically a covalent BTK inhibitor (cBTKi), a BCL2 inhibitor (BCL2i) and a non-covalent BTK inhibitor (ncBTKi). This study is designed as a potentially pivotal trial for Accelerated Approval in the United States and commenced in October 2025 upon agreement with the U.S. Food and Drug Administration (FDA) for the use of the 600mg, once daily dose of bexobrutideg as determined by our Phase 1b study of both a 200mg and a 600mg dose in patients in accordance with the FDA’s Project Optimus. In January 2024, the FDA granted Fast Track designation for bexobrutideg for the treatment of adult patients with relapsed or refractory chronic lymphocytic leukemia (CLL) or small lymphocytic lymphoma (SLL) after at least two lines of therapy, including a BTK inhibitor and a B-cell lymphoma 2 (BCL2) inhibitor. In November 2024, the European Medicines Agency (EMA) granted Priority Medicine (PRIME) designation for bexobrutideg in CLL or SLL after at least a BTK inhibitor and a BCL-2 inhibitor. In December 2024, the FDA granted Fast Track designation for bexobrutideg for the treatment of adult patients with Waldenstrom’s macroglobulinemia (WM) after at least two lines of therapy, including a BTK inhibitor.

Status of Zelebrudomide: We are currently conducting a Phase 1a/1b dose-escalation and cohort expansion study of zelebrudomide in patients with relapsed or refractory B-cell malignancies. We previously initiated Phase 1b expansion cohorts for patients with relapsed CLL, diffuse large B-cell lymphoma (DLBCL) and mantle cell lymphoma (MCL). Enrollment was paused in 2023 due to a partial clinical hold stemming from a manufacturing change designed to produce a chirally controlled form of zelebrudomide. Enrollment of new patients in this clinical trial recommenced in August 2024 following resolution of the partial hold by the FDA. Dose escalation with the new drug form is ongoing with a focus on patients with aggressive forms of B-cell lymphoma, such as DLBCL and MCL.

In addition to our BTK degrader portfolio, we are also advancing a novel immune-oncology inhibitor of the E3 ligase CBL-B. CBL-B is a RING-type E3 ligase that regulates the activation of multiple immune cell types including T cells and NK cells through protein degradation. NX-1607 is an orally bioavailable inhibitor of CBL-B that has the potential to reduce T cell anergy and promote anti-cancer immune cell activity. NX-1607 is currently being explored in a variety of solid tumor indications.

Status of NX-1607: We are currently conducting a Phase 1a/1b dose-escalation and cohort expansion study of NX-1607 in patients with a range of oncology indications. This study also includes a cohort within the Phase 1a dose escalation study testing NX-1607 in combination with paclitaxel, a taxane chemotherapy commonly used across a range of relapsed and refractory solid tumor indications. In 2022, NX-1607 was awarded an Innovation Passport from the United Kingdom (UK) Medicines and Healthcare products Regulatory Agency to accelerate time to market and facilitate patient access to novel drugs to treat serious and life-threatening diseases.

Preclinical Pipeline

In addition to our clinical stage drug candidates, we are advancing multiple preclinical-stage programs within our protein degradation portfolio, both on our own and with partners, by developing new targeted protein degraders and degrader antibody conjugates for several therapeutic indications that currently lack treatment options or where current therapies are ineffective. These existing and future programs have the potential to provide patients with better options in therapeutic indications with significant unmet needs, including cancer, inflammation, autoimmunity and other challenging therapeutic areas.

We have entered into several revenue generating collaborations with large biopharmaceutical companies, including Gilead, Sanofi and Pfizer, to leverage our DEL-AI platform for drug discovery. As of November 30, 2025, we have received a total of $482.0 million in non-dilutive financing from our collaborators, and we are eligible to receive up to $6.1 billion in potential future fees and milestone payments, as well as royalties on future product sales. We retain certain options for co-development, co-commercialization and profit sharing in the United States for multiple drug candidates pursuant to these collaborations.

Corporate Strategy

Our strategy is to discover and develop breakthrough therapies for patients with significant unmet clinical need by developing highly differentiated degrader-based medicines that alter or remove disease-causing or disease-associated biological targets that to date have been ineffectively drugged or have been considered undruggable with existing modalities. The key elements of our strategy are to:

•Advance our lead program, bexobrutideg, into late-stage clinical development in CLL and potentially other B-cell malignancies. Enrollment is ongoing in our Phase 2 clinical trial of bexobrutideg in adults with relapsed or refractory CLL. In 2026, we intend to commence enrollment of a suite of additional trials designed to support the potential future registration of the drug in multiple regulatory jurisdictions. We plan to leverage the Fast Track designation from the FDA in CLL and WM as well as the PRIME designation from the EMA to accelerate the clinical development and registrational path for bexobrutideg in oncology.

•Explore the therapeutic applications of bexobrutideg, for the treatment of patients with diseases caused by inflammation and autoimmunity. BTK mediates signaling downstream of the B-cell receptor (BCR), toll-like receptors (TLRs), and Fc receptors (FcRs), making it an attractive therapeutic target in antibody-mediated autoimmune and inflammatory diseases. Targeting BTK can reduce the production of new antibodies and mitigate inflammation induced by a variety of inflammatory signals, addressing key challenges in inflammatory and autoimmune diseases. We believe that bexobrutideg may offer unique advantages over currently available BTK inhibitors in these disease indications by addressing both the enzymatic and scaffold activities of BTK, which are key to its function. In 2025, we expanded the current Phase 1b trial in patients with CLL to include patients who are also suffering from immune-mediated cytopenias such as anemia, a common co-morbidity associated with CLL. In 2026, we may further explore the utility of bexobrutideg in autoimmune and inflammatory diseases with a separate clinical program which will require an IND with a separate division at the FDA.

•Continue development of zelebrudomide through dose escalation with a focus on aggressive lymphomas including MCL and DLBCL. Enrollment of new patients in our Phase 1a/1b clinical trial of NX-2127 has continued in adults with relapsed or refractory B-cell malignancies. In 2026, we expect to define doses to enable a Phase 1b cohort expansion.

•Continue development of NX-1607 through dose escalation in a range of solid tumor indications. Enrollment is ongoing in our Phase 1a/1b trial for NX-1607 in adults with multiple solid tumor types. In 2025, we continued dose escalation and expect to define doses and potential indications to enable a Phase 1b cohort expansion in 2026.

•Advance our portfolio of preclinical programs to generate development candidates and license agreements for our partnered pipeline. Our partnership efforts are focused on the advancement of a robust and sustainable pipeline in collaboration with our partners Gilead, Sanofi, and Pfizer. In our more mature partnerships with Gilead and Sanofi, multiple disclosed and undisclosed programs are advancing through lead optimization, IND-enablement and Phase 1 clinical studies. In March 2023, Gilead licensed our IRAK4 TPD program under the collaboration, and in April 2025 we announced FDA clearance of an IND for GS-6791/NX-0479 a novel IRAK4 degrader for inflammatory conditions. In addition, in March of 2024, Gilead extended the research term of multiple TPD programs. In April 2024, Sanofi extended its research term for a STAT6 targeted protein degrader and in June 2025 licensed a development candidate, NX-3911, and commenced IND enabling studies. In addition, Sanofi licensed a second program in May 2025 for an undisclosed target. In our partnership with Pfizer, which was announced in September 2023 under an agreement with Seagen, Inc., we have achieved three preclinical milestones to date, qualifying for $15.0 million in milestone payments. We expect to earn multiple additional preclinical and clinical milestones across our three active partnerships in 2026, which may allow us to secure additional license and development candidate events in 2026 and subsequent years.

•Advance our proprietary portfolio of preclinical programs toward additional INDs. The leading edge of our proprietary preclinical portfolio includes our pan-mutant BRAF program, which is designed to specifically target and degrade multiple mutant forms of the BRAF protein for the treatment of solid tumors including melanoma, colorectal cancer and non-small cell lung cancer. Lead compounds from this program show potency against the most common class I V600E BRAF mutation, but also potently degrade a broad spectrum of other BRAF driver mutations including those characterized as class II or III, all while sparing wild-type BRAF activity. The series of mutant BRAF degrader compounds has been optimized for oral bioavailability and CNS exposure, a profile that is critical in the setting of relapsed BRAF-driven disease. We believe our degraders will be clinically advantageous over existing therapies based on in vivo preclinical models that show improved potency against clinically relevant BRAF mutations and superior efficacy compared to other clinical and preclinical BRAF and RAF agents. Our BRAF degraders are likely to provide a greater therapeutic window compared to existing BRAF agents because they avoid paradoxical pathway activation while preserving normal wild-type BRAF function. We believe that a pan-mutant BRAF degrader will provide more sustained MAPK pathway suppression through its catalytic mechanism of action with the potential to target relapsed and refractory BRAF-mutant positive class I patient populations as well as class II and III BRAF patients for which there exists no approved BRAF therapies. In addition to targeted protein degraders of mutant BRAF, we are advancing multiple other proprietary programs targeting mutant proteins or other disease-drivers that are currently at various stages of preclinical discovery from DNA-encoded library screening to lead optimization and development candidate nomination.

•Build a leading platform for discovery of degrader antibody conjugates. DACs combine the selective and potent catalytic activity of targeted protein degraders with the cell- and tissue-specific delivery capabilities of antibodies. DACs represent the next generation of antibody drug conjugate technology that is designed to allow for the application of uniquely targeted payloads that can deliver more precise drug action while also providing multiple layers of cellular and molecular selectivity to potentially achieve both enhanced safety and improved efficacy. As part of our strategy to accelerate DAC discovery and demonstrate value, we have partnered with Pfizer, the leading pharmaceutical company in the antibody drug conjugate space, to advance this cutting-edge modality. By combining Nurix’s experience in machine learning, automated chemistry and targeted protein degraders with Pfizer’s expertise in antibody conjugate design, optimization and development, we believe we can achieve technical synergies that could allow us to redefine the application of antibody conjugates for not only oncology but also non-oncology indications.

•Grow our proprietary pipeline by expanding the capabilities of our DEL-AI platform. Targeted protein degradation is rapidly becoming the therapeutic modality of choice for an increasing list of pharmaceutical targets. To unlock the full potential of TPD, it is essential to have ready access to chemical starting points for biological pathways and targets that historically have been considered undruggable but now are rendered tractable by this more versatile approach. We believe we are uniquely positioned to identify novel chemical starting points to undruggable proteins and ligases. We have developed a suite of AI tools applicable across the breadth of our technical workflows, but with a specific focus on prospective ligand discovery informed by our years of accumulated DEL screening data and know-how. Using our SP3-enriched, proprietary DNA-encoded libraries and complementary E3 ligase-enriched DEL screening data, we have created a leading AI-powered platform which is designed to quickly generate multiple potential starting points for degrader drugs, thereby opening access to hundreds of unprecedented drug targets and target families. Further, the predictive power of this platform extends our drug development capabilities into a broadening range of induced proximity modalities including novel molecular glue degraders and protein stabilizers. Our DEL-AI platform can reduce reliance on serial wet-lab protein chemistry and screening efforts on challenging targets and instead can provide nearly instant access to drug-like and selective DEL binders to potentially any target or target class. By employing advanced machine learning models informed by empirical degrader assay datasets that we have amassed, which include a compendium of in vitro and in vivo pharmacokinetic and pharmacodynamic readouts from tens of thousands of targeted protein degrader compounds, we have the ability to reduce the number of design-make-test cycles in our optimization campaigns, eliminate optimization bottlenecks, and shorten the overall project timelines required to achieve desired TPD target product profiles. We plan to continue to invest in and leverage our purpose-built machine learning capabilities and DEL-AI research engine, which we believe will enable us to enhance our position as a leader in degrader drug discovery and deliver a robust and sustainable drug pipeline.

•Explore additional strategic collaborations to maximize the commercial potential of our existing pipeline assets as well as our DEL-AI and DAC platforms. As of November 30, 2025, wehave received a total of $482.0 million in non-dilutive funding from our collaborations, which has enabled us to invest in our own research and development activities. Under our Gilead, Sanofi and Pfizer collaborations, we have the potential to receive up to $6.1 billion in future fees and milestone payments, as well as royalties on future sales, and we retain certain options for co-development, co-commercialization and profit sharing in the United States for multiple drug candidates. We currently retain worldwide development and commercialization rights to our BTK and CBL-B clinical portfolios as well as numerous preclinical-stage projects, including our BRAF program. We intend to become a fully integrated biopharmaceutical company by building a targeted sales force in the United States and potentially other countries to support the commercialization of our approved drug candidates. In addition, we plan to selectively pursue technology collaborations and commercialization partnerships with partners whose capabilities complement our own, while retaining significant commercial rights in key geographic territories.

Our Clinical Programs

BTK’s role in B-cell malignancy

BTK is a key component of the B-cell receptor signaling pathway and has been clinically validated as a target in the treatment of B-cell malignancies, most notably in CLL but also in non-Hodgkin lymphoma (NHL). It is estimated that in 2024, in the United States, over 20,000 patients were diagnosed with CLL and over 80,000 patients were diagnosed with NHLs. Approximately 85% of NHLs are a result of B-cell malignancies. The natural progression of NHL varies widely and takes multiple forms, ranging from aggressive subtypes such as DLBCL, to more indolent forms such as follicular lymphoma (FL).

Background on BTK inhibitors and immunomodulatory drugs for B-cell malignancies

The first generation BTK inhibitor Imbruvica, or ibrutinib, is approved for the treatment of CLL, WM and chronic graft versus host disease. Second generation BTK inhibitors include Calquence, or acalabrutinib, which is approved for use in CLL and MCL, and Brukinsa, or zanubrutinib, which is approved for use in CLL, MCL, WM and marginal zone lymphoma (MZL). These BTK inhibitors bind covalently to cysteine C481 of the BTK protein and irreversibly inhibit BTK; however, all have some off-target binding to other kinases, which leads to unwanted side effects. In addition, acquired resistance, most commonly through mutations in C481, may limit the long-term efficacy of first and second generation covalent BTK inhibitors. A number of noncovalent BTK inhibitors are currently being investigated in clinical trials as potential therapies for patients with relapsed and refractory disease, including Jaypirca, or pirtobrutinib, which was recently approved for use in CLL and MCL. However, noncovalent inhibitors are also subject to acquired resistance, and treatment with such agents has led to the discovery of a broad range of new resistance mutations. Based on reported sales to date, we estimate that sales of BTK inhibitors were approximately $10.6 billion in 2024.

BTK degraders possess several unique properties that offer potential advantages over inhibitors:

•Addresses scaffold function of BTK. Removal of the BTK protein rather than inactivating the kinase domain addresses the scaffolding activity of BTK, more completely eliminating the signaling activity of both wild-type and mutant forms of BTK.

•Address BTK inhibitor resistance mutations through event-driven pharmacology. BTK degraders do not require strong and prolonged binding to BTK to trigger degradation, which increases the ability of degraders to act on mutated BTK and may decrease the probability of forming new resistance mutations.

•Catalytic activity. A single degrader molecule is able to trigger degradation of thousands of BTK target proteins sequentially without the need to be constantly bound to the target.

We believe that targeted protein degradation of BTK may be a superior approach to existing covalent or noncovalent BTK inhibitors as well as in the setting of resistance mutations to both covalent and noncovalent inhibitors.

Immunomodulatory drugs, including Revlimid, or lenalidomide, and Pomalyst, or pomalidomide, are analogs of Thalomid, or thalidomide. These drugs possess several anti-tumor properties, including anti-angiogenic and anti-proliferative effects. They also have multiple effects on the immune system, including the enhancement of T-cell mediated and NK-cell mediated immunity. Revlimid, the market leader in this class by global sales, was first approved in 2006 for the treatment of multiple myeloma. In May 2019, Revlimid in combination with Rituxan received a supplemental indication approval for previously treated FL, MZL and MCL, and in August 2020, Revlimid in combination with Monjuvi received a supplemental indication in DLBCL, thus validating the importance of this drug class in these indications. Based on reported sales to date, global sales of this drug class, including Revlimid and Pomalyst, peaked in 2021 at approximately $16.2 billion, prior to the introduction of generic competition. Subsequent to their approval and successful commercialization, studies demonstrated that these immunomodulatory drugs exert their therapeutic effect by triggering the degradation of specific proteins including Ikaros and Aiolos through the E3 ligase activity of cereblon, and hence were identified retrospectively as the first approved drugs to harness the activity an E3 ligase as a molecular glue.

Recently published studies have reported early clinical data showing that combining a BTK inhibitor with an immunomodulatory drug may have the potential to augment clinical activity of certain standard of care agents in some hematologic malignancies such as non-germinal center B-cell like (non-GCB) DLBCL. Further, earlier scientific publications have described synthetic lethality in a DLBCL cell line treated with both ibrutinib and lenalidomide. By targeting both BTK and cereblon-mediated immunomodulatory pathways simultaneously, it is believed that the survival mechanisms driven by accumulated mutations within certain cancers can be overcome, thereby preventing escape and disease relapse. This may be especially effective if each pathway not only has different functions but also shares certain critical components. One possible intersection pathway is the suppression of interferon regulatory factor 4 (IRF4), a member of a family of transcription factors leading to a cell-lethal increase in interferon production. The early clinical study referenced above was particularly noteworthy because, prior to that study, few combinations have produced promising results in DLBCL. The findings suggest that simultaneous degradation of BTK combined with cereblon-mediated immunomodulatory activity by a single agent could produce an additive or synergistic effect in certain B-cell malignancies.

Potential advantages of BTK degraders

We have conducted extensive preclinical studies of our two clinical stage BTK degraders. We have demonstrated that both bexobrutideg and zelebrudomide can induce BTK degradation and inhibit tumor growth with oral administration in xenograft mouse models implanted with both wild-type and ibrutinib-resistant lymphoma cell lines. We have also demonstrated the ability of both bexobrutideg and zelebrudomide to degrade BTK in circulating B cells of non-human primates and in B-cell lymphoma patients following once daily oral dosing in ongoing Phase 1 trials. We have specifically designed bexobrutideg to degrade BTK with limited or no degradation of cereblon neosubstrates.

We have designed zelebrudomide as a dual degrader of BTK and the cereblon neosubstrates Ikaros and Aiolos, for potential applications in indications where adding immunomodulatory activity may be beneficial.

We have optimized bexobrutideg and zelebrudomide to be able to degrade both wild-type BTK and the C481S variant of BTK that has been identified as the most common mutation in patients who have become resistant to ibrutinib therapy over time. Both agents have subsequently demonstrated the ability to degrade additional mutant variants of BTK associated with resistance to BTK inhibitors including L528W, T474I, M437R and V416L.

In our model of DLBCL cell line (TM8) harboring the most common resistance mutations, both bexobrutideg and zelebrudomide retained activity against all of the common clinical BTK inhibitor resistance mutations, while all tested inhibitors demonstrated a major decrease in activity against at least one of these prevalent mutations. The figure below shows a heat map of the relative activity of bexobrutideg compared to a panel of both covalent and non-covalent BTK inhibitors.

Clinical development studies for bexobrutideg

We are studying the pharmacology, safety, and clinical activity of bexobrutideg in multiple subtypes of relapsed and refractory B-cell malignancies, including those in which ibrutinib has shown only modest effects or is ineffective, as in the case of CLL patients with BTK inhibitor resistance mutations.

As illustrated in the diagram below, we are conducting a Phase 1a/1b dose-escalation and cohort expansion study of bexobrutideg in patients with relapsed or refractory CLL and NHL. We completed enrollment in the Phase 1a portion and commenced the Phase 1b portion of the trial in the second half of 2024 randomized between two once daily (QD) doses of 200 mg and 600 mg in patients with CLL. Additional cohorts of patients with CLL, MZL, FL, and WM were initiated at the 600mg QD dose. The patients in the study represent a heavily pre-treated population with a variety of previous treatments. Some patients also have mutations associated with BTK inhibitor resistance and other high risk molecular and clinical features. The study is currently enrolling in the United States, the UK, and in selected sites in Europe.

Bexobrutideg Phase 1 Clinical Study Design

Bexobrutideg Phase 1a clinical findings in chronic lymphocytic leukemia

Clinical findings from the bexobrutideg Phase 1a trial were presented at the 67th American Society of Hematology annual meeting in December 2025 (ASH 2025). These results included safety findings from a total of 126 CLL/SLL patients treated at all doses and 70 CLL/SLL patients treated at the 600mg dose, as of the September 19, 2025 data cut, and included efficacy findings from among the 47 CLL response evaluable patients enrolled in the Phase 1a at that time. Bexobrutideg was well tolerated across all doses evaluated, and safety findings in the CLL/SLL cohort were consistent with the overall population as well as previous safety analyses (see table below).

Bexobrutideg Comparable AE Profile for Patients Overall and at the 600mg Dose Selected per Project Optimus

a Purpura/contusion includes episodes of contusion or purpura; b Aggregate of ‘neutrophil count decreased’ or ‘neutropenia’; c Fatigue was transient; d Aggregate of ‘thrombocytopenia’ and ‘platelet count decreased’; e Aggregate of ‘rash’ and ‘rash maculopapular’ and ‘rash pustular’; f Aggregate of ‘COVID-19’ and ‘COVID-19 pneumonia’ AE, adverse event; RP2D, recommended Phase 2 dose; TEAE, treatment-emergent adverse event

Among the efficacy evaluable patients with CLL/SLL in the Phase 1a portion of the study (n=47), bexobrutideg treatment resulted in an objective response rate (ORR) of 83.0% across all doses tested including two complete responses (4.3%), with the majority of responses occurring at the first assessment (Week 8). The median progression free survival (PFS) was 22.1 months across all doses tested (50-600 mg, see tables below). Responses were observed across all populations regardless of prior treatment, baseline mutations, high-risk molecular features, or central nervous system (CNS) involvement. This includes patients with baseline BTK mutations associated with treatment resistance to both covalent and non-covalent BTK inhibitors. Robust BTK degradation was observed in all patients, including those with baseline BTK mutations.

Bexobrutideg Phase 1a Overall Response Assessment

a Patients who were treated with bexobrutideg having ≥1 post-baseline disease assessment or documented clinical PD. b Objective response rate was evaluated using iwCLL criteria and included CR + PR + PR-L. c Kaplan-Meier estimate

Emerging data from the randomized Phase 1b cohorts points to higher ORR and longer progression free survival at the 600 mg RP2D compared to the 200 mg dose.

Preliminary Efficacy in Phase 1b Randomized Cohort of 200mg vs. 600mg

a Objective response rate includes CR + nPR + PR + PR-L. CI, confidence interval; ORR, objective response rate; PFS progression free survival

Bexobrutideg Pivotal Phase 2 commencement

In October 2025, enrollment was initiated in the DAYBreak CLL-201 Phase 2 study (NCT07221500), evaluating bexobrutideg at the 600 mg recommended Phase 2 dose (RP2D) and designed to support accelerated approval of bexobrutideg in triple-exposed CLL/SLL patients (post cBTKi, ncBTKi and BCL-2i).

DAYBreak Phase 2 Study Designed to Support Accelerated Approval

r/r CLL, relapsed or refractory chronic lymphocytic leukemia; ORR, objective response rate; iwCLL, International Workshop on CLL; IRC, Independent Review Committee; QD,once daily; SLL, small lymphocytic lymphoma; cBTKi, covalent BTK inhibitor; ncBTKi, non-covalent BTK inhibitor; BCL-2i, BCL-2 inhibitor

Bexobrutideg Phase 1 clinical findings in Waldenström macroglobulinemia

Clinical findings from the bexobrutideg Phase 1 trial in patients with Waldenström macroglobulinemia (WM) were also presented at the 67th American Society of Hematology annual meeting in December 2025 (ASH 2025). These results, also from the September 19, 2025 data cut, included the baseline characteristics of the 31 patients with WM enrolled across both the Phase 1a and Phase 1b portions of the trial, primary efficacy analysis in all response-evaluable patients, and duration on study for all 31 patients. Among the 28 patients who were evaluable for response the ORR was 75.0% and for 23 patients with two or more response assessments the ORR was 82.6%. A steady reduction in IgM levels occurred in most patients starting from the first IgM assessment (four weeks) which continued to deepen at eight weeks and beyond. The median duration of response was not reached with 14 patients continuing on treatment for more than six months.

Clinical development of zelebrudomide

We are studying the pharmacology, safety and clinical activity of zelebrudomide in multiple subtypes of relapsed and refractory B‐cell malignancies, including CLL, DLBCL, MCL, MZL and FL. We plan to focus development in NHL indications where zelebrudomide shows evidence of compelling clinical activity and where there is high unmet need.

The Phase 1a/1b dose escalation and cohort expansion study was initiated in 2021. Enrollment was paused in the fourth quarter of 2023 due to a partial clinical hold stemming from a manufacturing change designed to produce a chirally controlled form of zelebrudomide. Enrollment of new patients in the zelebrudomide clinical trial recommenced in August 2024, following resolution of the partial hold by the FDA. Dose escalation with the new drug form is ongoing with a focus on patients with aggressive forms of B-cell lymphoma. As illustrated in the diagram below, the Phase 1a/1b trial is currently evaluating doses of the new drug product ranging from 100 mg to 450 mg, with potential expansion cohorts for patients with DLBCL, MCL, FL, MZL, and WM. Patients enrolled in the clinical study who are deriving clinical benefit on the original drug product may continue to receive treatment in accordance with the ongoing study protocol, however all new patients are being treated with the new drug product.

Zelebrudomide Phase 1 Study Design

aPlanned number of evaluable patients (i.e., meeting DLT evaluability criteria); bPlanned number of evaluable patients (i.e., meeting efficacy evaluability criteria)

CLL, chronic lymphocytic leukemia; DLBCL, diffuse large B-cell lymphoma; DLT, dose-limiting toxicity; FL, follicular lymphoma; MCL, mantle cell lymphoma; MTD, maximum tolerated dose; MZL, marginal zone lymphoma; PD, pharmacodynamics; PK, pharmacokinetics; PCNSL, primary central nervous system lymphoma; SLL, small lymphocytic lymphoma; WM, Waldenstrom's macroglobulinemia

Zelebrudomide Clinical findings

Positive data from the zelebrudomide clinical study was presented at the 65th ASH annual meeting in December 2023 (ASH 2023) and ASH 2024, in patients with NHL and CLL, confirming a manageable safety profile that is consistent with previous reports for BTK-targeted and immunomodulatory therapies.

BTK degradation was demonstrated at all dose levels in patient samples, as shown in the figure below.

Source: Danilov et al., ASH 2023, Poster #4463

Efficacy findings showed promising clinical activity: For patients with NHL, encouraging and durable responses were observed, including two complete responses and two partial responses, each at week eight. For patients with CLL, despite a median of five prior lines of treatment and BTK mutations present in 36% of patients, zelebrudomide treatment resulted in an objective overall response rate of 40.7%, including partial responses in 11 patients, with treatment ongoing in 13 patients. Tumor shrinkage and clinical responses were observed in patients regardless of prior lines of therapy or baseline BTK mutations.

Zelebrudomide NHL efficacy

Zelebrudomide CLL efficacy

Source: Danilov et al, ASH 2023, Poster #4463

Background on CBL-B as a regulator of T-cell activation

T cells are central to the cell-mediated adaptive immune response. Their activation, expansion, and function require carefully balanced positive and negative feedback mechanisms at each step. Multiple factors impair effective anti-tumor responses, including insufficient tumor antigen expression, defective antigen presentation, and the presence of inhibitory signals (e.g., immune checkpoints, suppressive factors, or T-cell exhaustion).

CBL-B is an E3 ubiquitin ligase expressed in multiple immune cell lineages, where it negatively regulates T-cell activation and limits the function of NK cells, B cells, and dendritic cells. By promoting T-cell exhaustion, anergy, and cell death, CBL-B downregulates immune responses. CBL-B is highly expressed in human CD4+ and CD8+ T cells, with its expression tightly regulated by co-stimulatory (CD28) and inhibitory (CTLA-4) signals.

Typically, T cells require two signals for activation: (1) TCR recognition of antigen–MHC complexes and (2) co-stimulatory signals. CBL-B influences the TCR pathway by requiring adequate co-stimulation for a full immune response. Accordingly, CBL-B–deficient T cells have reduced activation thresholds and resist T-cell anergy, displaying higher proliferation rates and elevated cytokine production (e.g., IL-2). However, inhibiting CBL-B alone does not activate T cells in the absence of TCR engagement, highlighting its potential as a therapeutic target to enhance anti-tumor immunity without indiscriminate T-cell activation.

Mechanism of action of NX-1607, an orally bioavailable small molecule inhibitor of the E3 ligase CBL-B

NX-1607: An Oral CBL-B Inhibitor for Immuno-Oncology

NX-1607 is an investigational, orally bioavailable, and potent CBL-B inhibitor that enhances T-cell-mediated anti-tumor responses. In vitro studies demonstrated that NX-1607 treatment resulted in a dose-dependent increase in T-cell activation in TCR-stimulated primary human T cells in the presence and, to a lesser extent, in the absence of CD28 co-stimulation, a potential advantage in a suppressive tumor microenvironment. NX-1607 does not appear to activate T cells in the absence of TCR engagement.

Clinical development of NX-1607

We are studying the pharmacology, safety and clinical activity of single-agent NX-1607 and have studied the combination of NX-1607 with taxane chemotherapy in multiple solid tumor indications. The solid tumors selected for this initial assessment include three different immune phenotypes: checkpoint-resistant tumors, tumors with an immunosuppressive microenvironment and tumors that are poorly immunogenic. We believe that there is a scientific rationale for the role of CBL-B inhibition in each of these immune phenotypes.

As illustrated in the diagram below, we are conducting a Phase 1a/1b dose-escalation and cohort expansion study of NX-1607 in patients with relapsed or refractory solid tumors and lymphoma. We are currently enrolling patients in the Phase 1a dose escalation portion of the monotherapy trial, which includes assessment of both once daily (QD) and twice daily (BID) dosing. We have also explored step-up dosing and the use of anti-emetic prophylaxis medication to achieve target drug levels and minimize potential gastrointestinal tolerability issues.

NX-1607 Phase 1a Clinical Study Design

Source: ECOG PS, Eastern Cooperative Oncology Group (ECOG) performance status

New Phase 1a clinical trial data for NX-1607 were presented at the European Society for Medical Oncology (ESMO) Congress and the 2025 Society for Immunotherapy of Cancer (SITC) Annual Meeting, demonstrating that NX-1607 exhibited dose-dependent pharmacologic activity consistent with target engagement and immune modulation, showing clinical activity through reductions in tumor-specific biomarkers such as prostate-specific antigen (PSA) in prostate cancer and carcinoembryonic antigen (CEA) in colorectal cancer. Notably, there was a confirmed partial response in a patient with micro-satellite stable colorectal cancer (MSS CRC), a tumor type typically unresponsive to immune checkpoint therapy. Furthermore, treatment with NX-1607 led to increased peripheral T cell activation and proliferation, significantly greater in patients with stable disease compared to those with progressive disease, indicating active T-cell receptor engagement and immune responsiveness. NX-1607 demonstrated on-target peripheral immune activation, suggesting its potential as an active immune-oncology agent with a unique mechanism distinct from PD-1/PD-L1 therapies. The data support the initiation of expansion cohorts at the two highest doses tested for both monotherapy and combination treatments in advanced solid tumors.

NX-1607 Demonstrates a Disease Control Rate of 49.3% Across Doses and Tumor Types

Our DEL-AI Platform and Research Engine

In disease settings where existing treatments are limited by suboptimal efficacy, safety, or rapid mutational resistance, or in settings that lack treatment options because the relevant disease drivers are not druggable by conventional means, we believe targeted protein degradation represents a promising treatment paradigm with the potential to greatly expand the number of pharmaceutically tractable biological disease targets and thereby significantly improve patient care. Early disclosures from an ever-increasing number of TPD clinical trials highlight the broad therapeutic potential of harnessing E3 ligases to promote targeted protein degradation of both established and unprecedented therapeutic targets. Using our DEL-AI research engine, we have identified many novel small molecule starting points and have progressed their development into differentiated therapies for patients lacking treatment options. Leveraging the wealth of chemical information that we have generated against hundreds of disease targets and E3 ligase proteins using our customized collection of 5 billion unique DEL compounds along with the knowledge we have accumulated by employing empirical degrader discovery workflows, we have constructed a powerful suite of machine learning models and tools that can enable us to predict proprietary binders for virtually any disease-relevant protein, including challenging targets like E3 ligases and transcription factors, and rapidly translate those binders into effective degrader drugs for a growing set of high value protein targets and target families. Our DEL-AI research engine is scalable and disease/target agnostic, providing us with the ability to support not only our wholly owned pipeline but also current and potential future discovery partnerships.

Fundamental premise of Nurix’s drug discovery: proteins as targets in treating disease

Each cell type within the body is comprised of proteins that define its biochemistry and biological function. When proteins are expressed and regulated correctly, the health of each individual cell as well as the body as a whole is maintained. However, disease can occur when normal cellular processes are dysregulated as a result of changes in protein structure, function, expression levels or pathway regulation. Factors such as genetic mutations, infection, exposure to toxins, diet and behavior can lead to dysregulation of cellular processes and, if unchecked, a disease process.

The traditional approach to discovering treatments for disease has involved the development of small molecule drugs that bind to a protein’s surface and modulate its activity. These “druggable” proteins contain distinct structural features called active sites that mediate protein function which can be exploited when identifying and optimizing compounds that disrupt protein activity. However, the vast majority of the body’s proteins do not have distinct active sites that can be targeted using traditional discovery methods. Because dysregulation and disease are not restricted to these “druggable” proteins, a significant number of therapeutically relevant proteins have not been addressed by traditional small molecule drugs. In addition, many existing small molecule drugs fail to fully block protein and pathway function, leading to incomplete disease resolution or rapid drug resistance. Other modalities, including antibody- and protein-based therapies, genetic medicines and cell therapies, have emerged to attempt to address these issues but are still limited by their modes of delivery, their scalability and their therapeutic applications.

Harnessing the activity of E3 ligases to create a new treatment modality

Normal cellular physiology requires highly orchestrated and regulated processes that operate at the level of individual proteins. The ability of proteins to respond to stimuli quickly and in a coordinated fashion requires protein function to be readily controllable. One of the most exquisitely ordered biochemical systems governing cellular protein activity is the ubiquitin proteasome system(UPS). A key class of enzymes within the UPS are E3 ligases which mediate this process with a high degree of specificity by recognizing individual proteins and catalyzing the attachment of ubiquitin protein tags to their surface. Proteins marked with chains of ubiquitin are then shuttled to the proteasome for degradation and removal from the cell. In addition to protein degradation, E3 ligases also mediate other functions such as protein localization, receptor internalization, protein signaling and protein quality control. There are over 600 E3 ligases encoded within the human genome, representing more than 5% of genes. The prevalence of the E3 ligase class of enzymes reflects the diversity of their physiological roles and biological significance and may allow for the creation of a wide spectrum of ligase-targeted therapeutics.

Controlling protein levels through small molecule therapeutics targeting E3 ligases

Advances in our understanding of the UPS suggest broad potential for the development of new therapies that co-opt E3 ligases in the context of diseases such as cancer and autoimmune disorders. An example are the so-called immunomodulatory drugs, Revlimid (lenalidomide) and Pomalyst (pomalidomide), which are approved cancer drugs. These drugs exert their therapeutic effects by binding to the E3 ligase cereblon and redirecting its activity toward proteins it would not normally degrade, known as neosubstrates, such as Ikaros and Aiolos (also known as IKZF1 and IKZF3), transcription factors regulating immune cell function. Elucidation of this mechanism led to the recognition that pharmacological control of E3 ligase activity could more generally represent a promising new paradigm for small molecule drug action. This idea has since translated into the development of a growing number of clinical stage targeted protein degraders, which we believe have significant therapeutic potential. In addition, we believe the largely unexplored area of inhibiting E3 ligases directly to modulate the levels of their native substrate proteins and potentially enhance pathway signaling may also represent a promising therapeutic approach.

•Harnessing E3 ligases to degrade pharmaceutically relevant proteins. Targeted protein degradation harnesses the natural activity of ligases to target novel neosubstrates, thereby removing specific proteins from the cell. Targeted protein degradation is accomplished by using a small molecule capable of creating a potent interaction between an E3 ligase and a Protein of Interest (POI) such that the E3 ligase can covalently label the POI with a ubiquitin chain, the cellular signal for proteasome-mediated destruction. Unlike traditional small molecule inhibition which requires prolonged active site occupancy, targeted protein degradation requires only a brief interaction with a POI, through event-driven pharmacology, allowing one degrader molecule to induce the degradation of hundreds to thousands of copies of the protein target in a catalytic fashion, thereby enabling complete elimination of a protein target and all of its associated functionality. Further, since the effect is mediated through binding rather than through enzymatic inhibition, proteins lacking enzymatic activity are targetable, greatly expanding the spectrum of both proteins and diseases amenable to small molecule therapeutic intervention. Some of the key advantages of targeted protein degradation over existing modalities are:

•Degraders can eliminate all of a protein’s functionality. Removing a protein from the cell by targeting it for proteasomal destruction eliminates all of a protein’s functionality, including scaffolding or structural functions, in contrast to small molecule inhibitors that only block enzymatic function.

•Degraders can access an expanded range of target space. Conventional small molecule drug development is limited to protein classes, typically enzymes, that exhibit biochemical activities that can be reliably measured and inhibited through the binding of a compound to the target’s active site. In contrast, proteasomal degradation of a target protein is accomplished by inducing brief proximity of the target protein to an E3 ligase, a process that is agnostic to target structure and function.

•Degraders show differentiated pharmacology. TPDs act catalytically to eliminate their corresponding target proteins from a cell, requiring just a few degrader molecules to eliminate thousands of protein molecules and forcing the cell to resynthesize the target protein to restore functionality. This creates a unique degrader pharmacokinetics and degrader pharmacodynamics, greatly reducing the amplitude and duration of drug exposure required to maintain target suppression as compared to traditional small molecule inhibitors.

•Degraders are mutationally tolerant. Minor changes in the amino acid sequence of a target protein, as a consequence of somatic or inhibitor-selected resistance mutations, do not necessarily preclude degrader activity, even in cases where the mutations occur within the degrader binding site. This desirable property relates to the event-driven pharmacology of degraders and is in stark contrast to the propensity of amino acid point mutations to disrupt the in vivo activity and efficacy of inhibitor drugs.

•Degraders can penetrate the CNS. Small molecule drugs and, most prominently beyond-the-rule-of-five compounds rarely achieve potent CNS exposure or activity. However, TPDs are increasingly cited for their ability to penetrate and show pharmacology in the CNS, in part due to the minimal plasma and cerebral spinal fluid (CSF) exposure required for these catalytic agents to exhibit target coverage.

•Inhibiting E3 ligases to control pathway activation. By inhibiting the function of E3 ligases it is possible to rapidly increase the levels of specific protein substrates to control biological pathways. Raising the levels of distinct sets of proteins within a single biological pathway could be a powerful approach to blocking pathological processes and restoring normal physiology. While there is enthusiasm in the scientific community around the therapeutic potential of E3 ligase inhibition, the discovery of such inhibitors has been impeded by the limited understanding of this biochemically and structurally complex class of proteins and the limited availability of chemical matter for this historically intractable protein class.

We believe that co-opting E3 ligase functionality to effect pharmaceutical control of critical disease-associated proteins represents a powerful therapeutic frontier that retains the favorable attributes of small molecule treatment modalities while addressing some major limitations. In addition to the points above, we believe other key differentiating attributes of our treatment modality include:

•Expansive therapeutic potential. The UPS and its associated E3 ligases function across the majority of cell types and organ systems, making it possible to modulate virtually any protein of interest for a wide range of diseases.

•Deliverable and tunable. Oral delivery of small molecule compounds lends itself to broad medical applicability in a range of patient populations with delivery that may be readily calibrated through dosing schedule and quantity.

•Ease of manufacturing. Development and manufacturing of small molecules utilizes established, cost-efficient processes that are readily scalable.

Key attributes and applications of our DEL-AI platform and research engine

Our approach to pharmaceutical development relies on harnessing the innate specificity and the natural function of the UPS to regulate the cellular proteome for therapeutic effect. Until recently, development of therapies that co-opt E3 ligases and other UPS effectors has been limited by the lack of available chemical matter for this class of proteins, as well as by the relative lack of biochemical, biological and mechanistic understanding of these critical protein families. Through our focused efforts and investment over the past several years, we have developed proprietary tools, in-depth knowledge and a wealth of chemical matter to enable the broader use of E3 ligases in drug discovery. In addition, we have further expanded our reach by leveraging our E3 ligase knowledge base using purpose-built machine learning to prospectively access even more chemical matter capable of engaging this highly sought-after therapeutic target class.

Significant investments in E3 ligase protein sciences and DEL methodology developments along with a liberal application of our DEL resource across hundreds of proprietary and partnered POIs has allowed us to generate large, high-quality datasets predominantly representing target classes relevant to protein degradation. Using advanced machine learning techniques trained on our DEL data compendium, we have developed powerful tools that can prospectively predict ligands to an arbitrarily large number of protein targets. This technology has greatly broadened the set of proteins ligandable by our methodologies, both in scope and in scale.

As shown below, these capabilities and insights have allowed us to develop DEL-AI, a powerful technology to identify and advance novel drug candidates.

Our DEL-AI research engine is a fully integrated, machine-learning powered drug discovery engine that leverages large empirical DEL and TPD datasets to write the rulebook of degrader drug design.

DEL technology taps enormous chemical space to overcome “druggability” limits

Our DEL compound collection comprises several billion individually DNA-labeled drug-like small molecules in contrast to conventional screening collections which contain less than a few million untagged compounds. This increased scale and traceability provides the necessary chemical diversity to identify chemical starting points for a broad set of biological targets, including many of the more challenging protein families that have been considered undruggable by other approaches. DEL technology evaluates each library compound simultaneously in a single experiment, enabling a more accurate biophysical assessment of compound behavior which translates into higher fidelity hit finding. In addition, because DEL drug discovery is performed by measuring compound binding rather than biochemical activity, it can be applied to almost any protein, most notably to proteins considered intractable because enzymatic screening assays are lacking or not feasible. Further, the relative ease with which binding screens can be performed and interpreted provides sufficient flexibility to allow evaluation of structurally complicated proteins like transcription factors and E3 ligases, which display distinct conformations and activity states that are rarely accessible in conventional biochemical screening assays. Lastly, a chemical linker attaches each DEL compound to a strand of DNA that functions as a barcode defining its unique chemical structure and allowing drug starting points to be easily identified through DNA sequencing. DEL’s built-in chemical linker is also an advantage in the context of TPD design, as it biases toward the discovery of binders that tolerate linker attachment, a critical prerequisite for bifunctional degrader construction.

Our DEL technology was designed to identify ligands to drug the undrugged

Our methods rely on proprietary DELs we have specifically engineered to enable access to selective binders for a diverse group of target protein classes, including transcription factors, E3 ligases, disease-specific mutant proteins including fusions, as well as many other targets that have not previously been drugged. Key features of our DEL platform include:

•Custom-synthesized DELs. Our libraries have been designed to incorporate hundreds of custom-synthesized chemical scaffolds that impart desirable, drug-like chemical properties like solubility into each library compound in a manner that cannot be achieved when building DEL collections solely from commercial inputs. The three-dimensional design of our proprietary, SP3-enriched scaffolds allows our DEL compounds to better-complement the shallow surfaces of these more difficult to drug protein types, making them ideal for hit finding screens directed against targets that have proven to be undruggable by conventional approaches. For 75% of the undruggable targets screened to date, our scaffold libraries have provided the sole source of progressible hits. Often these binders interact with previously unappreciated binding sites on the surface of the target protein, or they interact with rare or unexpected conformational states, offering new ways to potentially target disease processes specifically. Most importantly, using our collection of over 5 billion DNA-linked and readily traceable compounds in thousands of screen reactions has allowed us to amass an enormous compendium of highly ordered binding data that is directly applicable to machine learning.

Design and Differentiation of the Nurix DEL Collection

•Many screens, one protein target. Protein targets have many potentially ligandable surfaces and can also exist in multiple conformation states. Our approach uses comprehensive parallel screening campaigns to interrogate numerous states and surfaces of the target protein by combining multiple protein constructs with a variety of known substrates, binders, or cofactors in empirically replicated screening assays.

•Proprietary data analysis and hit confirmation technologies. We have built a suite of custom analytical tools for interpretation and prioritization of our DEL binder outputs, which routinely contain thousands of productive hits. By leveraging data collected from thousands of DEL screens, we can rapidly recognize and eliminate background signal and reveal the most promising target-specific ligands. We have also developed high throughput methods for nanoscale hit resynthesis and affinity selection mass spectroscopy that allow a more comprehensive and industrialized process for rapidly confirming the best chemical starting points for future pipeline programs.

Our ligase know-how enables us to address diverse therapeutic applications

We have expanded the universe of E3 ligases available for therapeutic manipulation from the two predominantly used in the field, cereblon and VHL, by screening more than 100 E3 ligases to date to identify novel harnesses or molecular glues for use in TPD. We have carefully selected these E3 ligases based on their potential degradative function, level of processivity, lack of regulation, and desirable cell or tissue expression pattern. We consider the unique biological function of each ligase and the therapeutic requirements of the disease state when prioritizing discovery workflows. E3 ligases that are required for cancer cell survival are also of high interest for cancer indications to reduce the risk of intrinsic resistance to degrader action. We continue to actively grow our collection of chemical matter for E3 ligases to better tailor our TPD product profiles to our expanding range of therapeutic areas.

Our industrialized degrader design, synthesis and testing workflows are scaled for empirical learning

•Rapid automated chemistry. Our advanced automated chemistry robotic suite allows for rapid synthesis of both binders and fully assembled degrader molecules. Application of on-resin chemistry methods allows us to achieve high reaction yields with fidelity such that we can forego purification steps and move rapidly from synthesis to cell-based testing of hundreds of degrader analogs per design cycle. This automation enables us to sample unprecedented chemical space and allows for faster design-make-test cycles, accelerating drug discovery projects.

•High throughput proteomics. A key advantage of the targeted protein degradation modality in contrast to traditional small molecule inhibitor development is that the precision and selectivity of protein degradation can be measured globally in any cell type to define on- and off-target drug behavior discretely at a cellular level, something not possible for nearly any other pharmaceutical modality. This proteome-wide data is ideally suited to inform machine learning models.

•Early and scaled in vivo pharmacokinetics and pharmacodynamics of bifunctional degraders. Our degrader optimization workflows employ high throughput in vivo screens for oral bioavailability which has enabled us to empirically determine the complex spectrum of property combinations that correlate with potent pharmacodynamic activity.

•Structure based drug design and ternary complex modeling. Ternary complex stability, optimal ligase-to-target protein orientation, and minimal degrader molecular weight are core tenets of any TPD discovery campaign. Our workflows prioritize the empirical determination of a variety of biophysical properties and behaviors, including protein x-ray structures, ternary complex x-ray or cryo-EM structures, and an array of protein-protein and ligand-protein modeling exercises that deliver valuable datasets for informing TPD design.

Cohesive integration of advanced machine learning to every aspect of our discovery process

Targeted protein degradation has unlocked novel avenues for delivering effective therapies, leveraging unprecedented mechanisms of action to eliminate disease-causing proteins. These molecules involve new biology and new chemistry, necessitating extensive research along many dimensions of our drug candidates to achieve desirable profiles for our TPDs. To navigate this new paradigm in drug discovery, we have taken an empirical approach. We have invested heavily in high-throughput data generation workflows such as our 5 billion compound DEL resource as well as our automated chemistry and assay platforms. As a result, we have amassed one of the industry’s largest datasets singularly generated from experiments relevant to discovery, validation and optimization of targeted protein degradation.

Our research engine harnesses our expansive, empirical data streams to write the rulebook for TPD drug design. Through the integration of high-quality data emerging from our discovery and development workflows and application of deep learning and generative design, our powerful research engine is delivering a rapidly growing portfolio of early leads and optimized drug candidates.

•DEL Foundation. A foundation machine learning model built on our high-quality and high-volume DEL datasets which enables prospective binder identification for diverse POI and Ligase targets.

•Degrader activity. Program-specific models trained on our proprietary degrader activity datasets to better understand and optimize degrader MOA.

•Multiparameter property optimization. A suite of models tuned to predict a range of important molecular and pharmacokinetic properties in the unique chemical space occupied by TPD molecules.

•Generative molecular design. An integrated infrastructure leveraging the range of DEL Foundation, Degrader Activity, and Property Optimization models within an advanced generative machine learning framework.

•Harnessing our data generation pipelines with machine learning. Our investment in scalable science has created large data streams stemming from our DEL, automated chemistry, and high-throughput experimental platforms. As a result, Nurix has amassed one of the industry’s largest datasets singularly generated from experiments relevant to targeted protein degradation. Through the integration of this data spanning the range of our degrader development activities with deep learning and generative design, our researchers leverage our machine learning platform to identify and deliver novel, optimized compounds at any stage along the research pipeline.

Our DAC platform can drive the discovery of cell-specific targeted therapies with the potential for an increased therapeutic windows

Antibody drug conjugates (ADCs) are a rapidly growing modality in targeted therapy. Traditional ADCs combine the selectivity of monoclonal antibodies with the potency of broadly cytotoxic payloads to effect malignant cell killing. While this modality can be agnostic to oncogenic mechanism, the pleiotropic effects of these payloads cannot be completely controlled by delivery, and therefore often lead to dose-limiting toxicity. We believe DACs, formed by conjugating a disease- or cell-type-selective antibody to a targeted protein degrader, can overcome the limitations of traditional ADCs. First, the degrader payload of a DAC swaps the polypharmacology of a payload toxin, not all of which is required for disease control, with the potent and precise pathway blockade that can be achieved by targeted protein degradation. Second, since degraders are catalytic, delivery of just a few degrader molecules to any one cell is sufficient to catalyze complete removal of a target protein and provide prolonged pharmacodynamic effect. Third, the tissue distribution of the degrader target protein and the co-opted E3 ligase afford two additional layers of selectivity to delimit DAC activity beyond what can be achieved through antibody delivery alone, mitigating the common ADC toxicities and providing the potential for superior safety while maintaining ADC-equivalent biological potency. In comparison, other novel antibody payloads, such as enzyme inhibitors, require high levels of payload delivery to be effective. An added benefit of the DAC modality is that it expands the repertoire of biological targets and E3 ligases that would make suitable combinations to achieving disease efficacy through TPD. This added flexibility enables us to further tap the potential of our DEL-AI platform to harvest a larger spectrum of Nurix’s existing chemical matter and know-how.

As a proof-of-concept for the DAC approach, we conjugated one of our potent BTK degraders to B-cell targeting (anti-CD19) and non-targeting (anti-Her2) monoclonal antibodies via a diverse set of chemical linkers leveraging our existing platform capabilities. The resulting B-cell targeting anti-CD19-BTK DACs, and non-targeting anti-Her2-BTK control conjugates were tested for BTK degradation in CD19+ malignant B cells. As illustrated in the figure below, we were able to show that only the anti-CD19 DAC (blue) had comparable degradation potency to that of the unconjugated degrader, validating the power and feasibility of antigen-specific antibody-mediated delivery of the DAC approach.

Collaborations and License Agreements

Gilead

In June 2019, we entered into a global strategic collaboration agreement with Gilead (as subsequently amended, the Gilead Agreement) to discover, develop and commercialize a pipeline of targeted protein degradation drugs for patients with cancer and other challenging diseases using our DEL-AI platform to identify novel agents that utilize E3 ligases to induce degradation of five specified drug targets. In August 2019 and September 2022, we entered into the First Amendment and the Second Amendment, respectively, to the Gilead Agreement to clarify certain language of the Gilead Agreement. In February 2024 and March 2024, as part of the existing collaboration agreement, Gilead elected to extend the five-year initial research term by two years for certain drug targets (Gilead Research Term Extension). The Gilead Research Term Extension triggered a $15.0 million payment, which we received in the second quarter of fiscal year 2024.

Under the Gilead Agreement, Gilead has the option to license drug candidates directed to up to five targets resulting from the collaboration and is responsible for the clinical development and commercialization of drug candidates resulting from the collaboration. We retain the option to co-develop and co-promote, under a profit share structure, up to two drug candidates in the United States, provided that we may only exercise such option once per licensed product and Gilead retains the right to veto our option selection for any one drug candidate of its choice. The collaboration excludes our current internal protein degradation programs for which we retain all rights, and also excludes our future internal programs, provided that we have distinguished future programs as excluded from the scope of the collaboration. In March 2023, Gilead exercised its option to exclusively license one target (Gilead License Option Exercise), the first development candidate resulting from the Gilead Agreement. Pursuant to the Gilead Agreement, we received a license option exercise payment of $20.0 million in April 2023 for the Gilead License Option Exercise.

Over time, Gilead may elect to replace the initial drug targets with other drug targets. For drug targets that are subject to the collaboration, we are obligated to use commercially reasonable efforts to undertake a research program in accordance with a research plan agreed to by the parties and established on a target-by-target basis. We have primary responsibility under the Gilead Agreement for performing preclinical research activities (including target validation, drug discovery, identification or synthesis) pursuant to a research plan. Each party will bear its own costs in the conduct of research activities. Gilead will be responsible for any development, commercialization and manufacturing activities, unless we exercise our co-development and co-promotion option. For those programs that we exercise our option to co-develop and co-promote, we and Gilead will split U.S. development costs as well as U.S. profits and losses evenly, and we will be eligible to receive royalties on net ex-U.S. sales and reduced milestone payments.

Upon signing the Gilead Agreement, Gilead paid us an upfront payment of $45.0 million, plus $3.0 million in additional fees. In addition, from the signing of the Gilead Agreement to November 30, 2025, we received payments of $47.0 million for research milestones and additional payments, $20.0 million for a license option exercise payment, $15.0 million in research term extension fees and $5.0 million for a clinical milestone payment. As of November 30, 2025, we are eligible to receive up to approximately $1.8 billion in total additional payments based on certain additional fees, payments and the successful completion of certain preclinical, clinical, development and sales milestones. We also are eligible to receive mid-single digit to low tens percentage tiered royalties on annual net sales from any commercial products directed to the optioned collaboration targets, subject to certain reductions and excluding sales in the United States of any products for which we exercise our option to co-develop and co-promote, for which the parties share profits and losses evenly.

Subject to earlier expiration in certain circumstances, the Gilead Agreement expires on a licensed product-by-licensed product and country-by-country basis upon the later of (1) the expiration of the last to expire patent with a valid claim covering the applicable licensed product in the applicable country, (2) the expiration of any regulatory exclusivity for the applicable licensed product in the applicable country or (3) ten years after the first commercial sale of the applicable licensed product in the applicable country covered by the Gilead Agreement, provided that the term for any profit-shared licensed product in the United States will expire upon the expiration or termination of the applicable profit-share term as set forth in an applicable profit-share agreement to be negotiated upon our exercise of our option to co-develop and co-promote such licensed product. If Gilead does not exercise an option to license a drug candidate, then the Gilead Agreement will terminate at the end of the last to expire option period.

Sanofi

In December 2019, we entered into a strategic collaboration with Genzyme Corporation, a subsidiary of Sanofi, which became effective in January 2020 (as subsequently expanded and amended, the Sanofi Agreement), to discover, develop and commercialize a pipeline of targeted protein degradation drugs for patients with challenging diseases in multiple therapeutic areas using our DEL-AI platform to identify small molecules designed to induce degradation of three specified initial drug targets. In January 2021, as part of the existing Sanofi Agreement, Sanofi paid us $22.0 million to exercise its option to expand the number of targets in the Sanofi Agreement from three to a total of five targets.

In January 2021, we entered into the First Amendment to the Sanofi Agreement to modify the research term on all targets. In December 2021, we entered into the Second Amendment to the Sanofi Agreement to extend the substitution deadline on certain targets. In July 2022, we entered into the Third Amendment to the Sanofi Agreement to further extend the substitution deadline on certain targets. Also in July 2022, Sanofi elected to replace certain drug targets, and the substitution extended the research term of those targets by one year to 5.25 years. In August 2022 and November 2023, we entered into the Fourth Amendment and Fifth Amendment, respectively, to the Sanofi Agreement to modify the research plan for certain targets. In March 2024, we entered into the Sixth Amendment to the Sanofi Agreement to extend the research term for the collaboration target STAT6 (signal transducer and activator of transcription 6), a key drug target in type 2 inflammation, by two years.

Under the Sanofi Agreement, Sanofi has exclusive rights and is responsible for the clinical development, commercialization and manufacture of drug candidates resulting from the collaboration while we retain the option to co-develop, co-promote and co-commercialize all drug candidates in the United States directed to up to two targets, one of which must be selected from a list of targets designated at the execution of the Sanofi Agreement or any replacement of such targets, and one of which must be selected from targets identified by Sanofi as part of their January 2021 expansion. Our right to exercise our option to co-develop, co-promote and co-commercialize a given target is dependent on our ability to demonstrate, within a given timeframe, that we have sufficient cash resources and personnel to commercialize the product. The collaboration excludes our current internal protein degradation programs for which we retain all rights, and also excludes our future internal programs, provided that we distinguished future programs as excluded from the scope of the collaboration.

In March 2025, Sanofi exercised its right to exclusively license one target (the First Sanofi License Extension), the first development candidate resulting from the Sanofi Agreement. Pursuant to the Sanofi Agreement, we received a license extension fee payment of $15.0 million in March 2025 for the First Sanofi License Extension. In May 2025, Sanofi exercised its right to exclusively license a second target (the Second Sanofi License Extension, and together with the First Sanofi License Extension, the Sanofi License Extensions), the second development candidate resulting from the Sanofi Agreement. Pursuant to the Sanofi Agreement, we received a license extension fee payment of $15.0 million in June 2025 for the Second Sanofi License Extension. The license to the functional intellectual property and all goods and services related to both the First Sanofi License Extension and the Second Sanofi License Extension were transferred during the second quarter of fiscal year 2025.

For drug targets that are subject to the collaboration, we have primary responsibility for conducting preclinical research activities (including target validation, drug discovery, identification or synthesis) in accordance with the applicable research plan agreed to by the parties and established on a target-by-target basis. We are obligated to use commercially reasonable efforts to identify relevant target binders and targeted protein degraders in order to identify development candidates. Subject to certain exceptions, each party will bear its own costs in the conduct of such research. Sanofi will be responsible for any development and commercialization activities unless we exercise our co-development and co-promotion option. For those programs that we exercise our option to co-develop, co-promote and co-commercialize, we will be responsible for a portion of the U.S. development costs, the parties will split U.S. profits and losses evenly, and we will be eligible to receive royalties on ex-U.S. net sales and reduced milestone payments on such optioned products.

Upon signing the Sanofi Agreement, Sanofi paid us an upfront payment of $55.0 million. Subsequently in January 2021, Sanofi paid us an additional $22.0 million to exercise its option to expand the number of targets beyond the initial targets included in the collaboration. In addition, from the signing of the Sanofi Agreement to November 30, 2025, we received payments of $20.0 million for research milestones and $30.0 million for license extension fees. As of November 30, 2025, we are eligible to receive up to approximately $930.0 million in total additional payments based on certain additional fees, payments and the successful completion of certain research development, regulatory and sales milestones. We are also eligible to receive mid-single digit to low teen percentage tiered royalties on annual net sales of any commercial products that may result from the collaboration, subject to certain reductions and excluding sales in the United States of any products for which we exercise our option to co-develop and co-promote, for which the parties share profits and losses evenly.

Subject to earlier expiration in certain circumstances, the Sanofi Agreement expires on a licensed product-by-licensed product or profit-shared licensed product-by-profit-shared licensed product basis and country-by-country basis upon on the later of (1) the expiration of the last-to-expire patent with a valid claim covering the applicable licensed product in the applicable country, (2) the expiration of any regulatory exclusivity for the applicable licensed product in the applicable country or (3) ten years after the first commercial sale of the applicable licensed product in the applicable country covered by the Sanofi Agreement.

Pfizer

In September 2023, we entered into a strategic collaboration with Seagen Inc. (now a part of Pfizer Inc.) (the Pfizer Agreement) to develop a suite of targeted protein degraders against multiple targets nominated by Pfizer that are suitable for antibody conjugation. Pfizer will be responsible for conjugating these degraders to antibodies to make DACs, a new class of medicines for use in cancer treatment and advancing these DAC drug candidates through preclinical and clinical development and commercialization.

Under the Pfizer Agreement, Pfizer has the option to obtain exclusive licenses to develop and commercialize certain degraders, while we retain an option for U.S. profit sharing and co-promotion on two products arising from the collaboration. The collaboration excludes our current internal protein degradation programs for which we retain all rights, and also excludes our future internal programs, provided that we have distinguished future programs as excluded from the scope of the collaboration.

For the targets nominated by Pfizer under the collaboration, we shall use commercially reasonable efforts to identify, synthesize, characterize and deliver targeted protein degraders that selectively bind to and degrade such targets. Development of licensed degraders, with the exception of licensed products for which we exercise our profit-share options, will be at Pfizer’s sole cost and expense. For the profit-share products, the parties will share net profits and net losses and global development costs, and we will be eligible to receive royalty and milestone payments on such optioned products.

Under the terms of the Pfizer Agreement, we received an upfront payment of $60.0 million. In addition, from the signing of the Pfizer Agreement to November 30, 2025, we received payments of $10.0 million for research milestones. We are eligible to receive up to approximately $3.4 billion in contingent payments based on specified research, development, regulatory and commercial milestones across multiple programs. We are also eligible for mid-single to low double digit percentage tiered royalties on future sales.

Subject to the exceptions described in the Pfizer Agreement, the Pfizer Agreement expires upon the first to occur of (1) the expiration of the last-to-expire option exercise period under the Pfizer Agreement if no such option has been exercised prior to such expiration and (2) the expiration of the last-to-expire royalty term under the Pfizer Agreement.

Manufacturing and Supply

We do not own or operate, and currently have no plans to establish, any facilities for product manufacturing, packaging, storage and distribution, or testing. We rely on and expect to continue to rely on contract manufacturing organizations (CMOs) for both drug substance and finished drug product. We have personnel or engaged consultants with extensive technical, manufacturing, analytical and quality experience and good project management to oversee contract manufacturing and testing activities. We have engaged third-party manufacturers to supply the drug substances for bexobrutideg, zelebrudomide, and NX-1607 and to develop and manufacture finished drug products for use in our clinical trials. Should any of these manufacturers become unavailable to us for any reason, we believe that there are a number of potential replacements, although we may incur some delay in identifying and qualifying such replacements.

All of our drug candidates are organic compounds of low molecular weight, generally called small molecules, but which are larger than traditional small molecule therapeutics. We have selected these compounds not only on the basis that they could have potentially favorable efficacy and safety profiles, but also for their ease of synthesis and the reasonable cost of their starting materials. In particular, our lead drug candidates are manufactured using reliable and reproducible synthetic processes from readily available starting materials. The chemistry is amenable to scale up and does not require unusual equipment in the manufacturing process. We expect to continue to develop drug candidates that can be produced cost-effectively at contract manufacturing facilities.

Competition

The biotechnology and biopharmaceutical industries are characterized by rapidly advancing technologies, intense competition and a strong emphasis on intellectual property and proprietary products. While we believe that our technology, development experience, scientific knowledge and intellectual property portfolio provide us with competitive advantages, we face potential competition from many different sources, including major pharmaceutical, specialty pharmaceutical and biotechnology companies, academic institutions, governmental agencies and public and private research institutions that conduct research, seek patent protection and establish collaborative arrangements for research, development, manufacturing, and commercialization. Not only must we compete with other companies that are focused on protein degradation, but any drug candidates that we successfully develop and commercialize will compete with existing therapies and new therapies that may become available in the future. Moreover, our industry is characterized by the existence of large numbers of patents and frequent allegations of patent infringement.

Our focus is the discovery and development of innovative small molecules and antibody therapies designed to degrade protein levels, including targeted protein degraders. We are aware of multiple companies that primarily focus on developing small molecules that degrade target proteins. Drug candidates from our BTK degrader and CBL-B inhibitor programs may face competition from drugs with similar mechanisms of action. We are also aware of clinical-staged BTK degraders currently in development by multiple companies, and we are aware of at least once company currently developing a clinical-staged CBL-B inhibitor.

Our lead drug candidates target hematologic cancers and immune-mediated diseases. The most common methods of treating patients in oncologic indications are surgery, radiation and drug therapy, including chemotherapy, hormone therapy and targeted drug therapy. There are a variety of available drug therapies marketed for cancer, including hematologic cancers. In many cases, these drugs are administered in combination to enhance efficacy. Some of the currently approved drug therapies are branded and subject to patent protection, and others are available on a generic basis. Many of these approved drugs are well established therapies and are widely accepted by physicians, patients and third-party payors. In general, although there has been considerable progress over the past few decades in the treatment of cancer and the currently marketed therapies provide benefits to many patients, these therapies all are limited to some extent in their efficacy and frequency of adverse events, and none of them are successful in treating all patients. As a result, the level of morbidity and mortality from cancer remains high.

In addition to currently marketed drugs, there are also several drug candidates in late-stage clinical development for the treatment of oncologic indications and immune-mediated diseases. These products in development may provide efficacy, safety, convenience and other benefits that are not provided by currently marketed therapies. As a result, they may provide significant competition for any of our drug candidates for which we obtain market approval.

If any of our drug candidates are approved for the indications for which we currently are conducting clinical trials or for which we expect to conduct clinical trials, they will compete with the foregoing therapies and the currently marketed drugs and potentially any drugs in development. It is also possible that we will face competition from other biologic or pharmaceutical approaches as well as from other types of therapies.

Many of our current or potential competitors, either alone or with strategic partners, have significantly greater financial resources and expertise in research and development, manufacturing, preclinical testing, conducting clinical trials, obtaining regulatory approvals and marketing approved products than we do. These competitors also compete with us in recruiting and retaining qualified scientific and management personnel and establishing clinical trial sites and patient registration for clinical trials, as well as in acquiring technologies complementary to, or necessary for, our programs. Mergers and acquisitions in the pharmaceutical and biotechnology industries may result in even more resources being concentrated among a smaller number of our competitors. Smaller or early-stage companies may also prove to be significant competitors, particularly through collaborative arrangements with large and established companies. Our commercial opportunities could be reduced or eliminated if our competitors develop and commercialize products that are safer, more effective, have fewer or less severe side effects, are more convenient or are less expensive than any products that we may develop. Our competitors also may obtain FDA or other regulatory approval for their products more rapidly than we may obtain approval for ours, which could result in our competitors establishing a strong market position before we are able to enter the market. In addition, our ability to compete may be affected in many cases by insurers or other third-party payors seeking to encourage the use of generic products. There are generic products currently on the market for certain of the indications that we are pursuing, and additional products are expected to become available on a generic basis over the coming years. If our drug candidates are approved, we expect that they will be priced at a significant premium over competitive generic products.

The key competitive factors affecting the success of all our programs, if approved, are likely to be their efficacy, safety, convenience, price, level of generic competition and availability of reimbursement.

Intellectual Property

We strive to protect and enhance the proprietary technology, inventions, platforms, drug candidates and improvements thereof that are commercially important to our business, including obtaining, maintaining and defending patent rights, whether developed internally or licensed from third parties. Our policy is to seek to protect our proprietary position by, among, other methods, pursuing patent protection in the United States and in jurisdictions outside of the United States related to our proprietary technology, inventions, improvements, platforms and drug candidates that are important to the development and implementation of our business. Our patent portfolio is intended to cover, but is not limited to, our technology platforms, drug candidates and components thereof and their methods of use, and any other inventions that are commercially important to our business.

We also rely on trade secret protection of our confidential information and know-how relating to our proprietary technology, platforms and drug candidates and continuing innovation to develop, strengthen and maintain our position in our DEL-AI platform and drug candidates. Trade secrets are difficult to protect and provide us with only limited protection. 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 or controlled by third parties; to defend and enforce our proprietary rights, including our patent applications; to defend against challenges and assertions by third parties of their purported intellectual property rights; and to operate without infringement of valid and enforceable patents and other proprietary rights of third parties. For risks related to our intellectual property, please see “Risk Factors—Risks Related to Our Intellectual Property.”

We believe that we have a strong global intellectual property position and substantial know how and trade secrets relating to our DEL-AI platform and drug candidates. As of December 31, 2025, we have 12 U.S. patents, 24 U.S. patent applications, 23 foreign patents and 121 foreign applications that we own, three U.S. patents, eight pending U.S. patent applications, five foreign patents and 88 foreign patent applications that we co-own with Gilead. The expected expirations for issued patents and patents that may issue from pending applications covering our clinical candidates are between the years 2039 and 2044 for bexobrutideg; 2039 and 2042 for zelebrudomide; and 2040 and 2043 for NX-1607.

The term of individual patents depends upon the laws of the countries in which they are obtained. In most countries in which we file, including the United States, the patent term is 20 years from the earliest date of filing of a non-provisional patent application in the applicable country. However, the patent term of U.S. patents may, in certain cases, be adjusted for administrative delays by the United States 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, the term of a patent may be extended as compensation for the patent term lost during the FDA regulatory review process. For example, for drugs that are regulated by the FDA under the Hatch-Waxman Act, it is permitted to extend the term of a patent that covers such drug for up to five years beyond the normal expiration date of the patent. For more information on patent term extensions, see “Business—Government Regulation—The Hatch-Waxman Act—Patent term extension.” In the future, if and when our pharmaceutical drug candidates receive FDA approval, we expect to apply for patent term extensions on patents, if issued, covering those drug candidates. We intend to seek patent term extensions to any of our patents, if issued, in any jurisdiction where these are available; however, there is no guarantee that the applicable authorities, including the USPTO and FDA, will agree with our assessment of whether such extensions should be granted, and even if granted, the length of such extensions.

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 also rely on trade secret protection for our know-how, confidential and proprietary information and continuing technological innovation to develop and maintain our competitive position. We seek to protect and maintain the confidentiality of proprietary information to protect aspects of our business that are not amenable to, or that we do not consider appropriate for, patent protection. Although we take steps to protect our confidential and proprietary information as trade secrets, including through contractual means with our employees, consultants, outside scientific collaborators, sponsored researchers and other advisors, competitors or other third parties may independently develop substantially equivalent proprietary information and techniques or otherwise gain access to our trade secrets or disclose our technology. Thus, we may not be able to meaningfully protect our trade secrets. It is our policy to require our employees, consultants, outside scientific collaborators, sponsored researchers and other advisors to execute confidentiality agreements under the commencement of employment or consulting relationships with us. Despite these efforts, we cannot provide any assurances that all such agreements have been duly executed, and any of these parties may breach the agreements and disclose our proprietary information, and we may not be able to obtain adequate remedies for such breaches. 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. 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 relation to the resulting know-how or inventions. For more information, please see the sections titled “Risk Factors—Risks Related to Our Intellectual Property” and “Risk Factors—Risks Related to Regulatory Approval and Marketing of Our Drug Candidates.”

Government Regulation

The processes for obtaining regulatory approvals in the United States and in foreign countries and jurisdictions, along with subsequent compliance with applicable statutes and regulations and other regulatory authorities, require the expenditure of substantial time and financial resources.

FDA approval process

In the United States, biological and pharmaceutical products are subject to extensive regulation by the FDA. The Federal Food, Drug, and Cosmetic Act (FDCA), Public Health Service Act (PHSA), and other federal and state statutes and regulations govern, among other things, the research, development, testing, manufacture, quality control, packaging, storage, recordkeeping, approval, labeling, promotion, advertising and marketing, distribution, post-approval monitoring and reporting, sampling, tracking and tracing and import and export of biological and pharmaceutical products. Failure to comply with applicable U.S. requirements may subject a company to a variety of administrative or judicial sanctions, such as FDA refusal to approve pending new drug applications (NDAs) or biologics licensure applications (BLAs), withdrawal of an approval, imposition of a clinical hold, warning or untitled letters, product recalls, product seizures, total or partial suspension of production or distribution, injunctions, fines, refusals of government contracts, restitution, disgorgement of profits or civil or criminal investigations and penalties brought by the FDA and the Department of Justice (DOJ) or other governmental entities.

Biological or pharmaceutical product development for a new product or certain changes to an approved or licensed product in the United States typically involves preclinical laboratory and animal tests, the submission to the FDA of an IND which must become effective before clinical testing may commence, and adequate and well-controlled clinical trials to establish the safety and effectiveness of a drug, or the safety, purity, or potency of a biological product, for each indication for which FDA approval is sought. Satisfaction of FDA pre-market approval and licensure requirements typically takes many years and the actual time required may vary substantially based upon the type, complexity and novelty of the product or disease.

Preclinical tests include laboratory evaluation of product chemistry, formulation and toxicity, as well as in vitro and animal trials to assess the characteristics and potential safety and efficacy of the product for initial testing in humans and to establish a rationale for therapeutic use. The conduct of the preclinical tests must comply with federal regulations and requirements, including Good Laboratory Practices (GLPs). The results of preclinical testing are submitted to the FDA as part of an IND along with other information, including information about product chemistry, manufacturing and controls, and a proposed clinical trial protocol. Long-term preclinical tests, such as animal tests of reproductive toxicity and carcinogenicity, may continue after the IND is submitted.

An IND is an exemption from the FDCA that allows an unapproved new drug or biological product to be shipped in interstate commerce for use in an investigational clinical trial and a request for FDA authorization to administer an investigational drug or biological product to humans. Such authorization must be secured prior to interstate shipment and administration of any new drug or biological product that is not the subject of an approved NDA or BLA. In support of a request for an IND, a sponsor must submit a protocol for each clinical trial and any subsequent protocol amendments must be submitted to the FDA as part of the IND. The sponsor may be a company seeking to develop the drug or biological product or, as in the case of an investigator-initiated trial, the sponsor may be an investigator who is conducting the trial. In addition, the results of the preclinical tests, together with manufacturing information, analytical data, any available clinical data or literature and plans for clinical trials, among other things, are submitted to the FDA as part of an IND.

A 30-day waiting period after the submission of each IND is required prior to the commencement of clinical testing in humans. This waiting period is designed to allow the FDA to review the IND to determine whether human research subjects will be exposed to unreasonable health risks. At any time during this 30-day period, the FDA may raise concerns or questions about the conduct of the trials as outlined in the IND and impose a clinical hold. In this case, the IND sponsor and the FDA must resolve any outstanding concerns before clinical trials can begin. If the FDA has neither commented on nor questioned the IND within this 30-day period, the clinical trial proposed in the IND may begin.

Clinical trials involve the administration of the investigational new drug or biological product to healthy volunteers or patients under the supervision of a qualified investigator. Clinical trials must be conducted: (i) in compliance with federal regulations; (ii) in compliance with good clinical practice (GCP), which is an international standard meant to protect the rights and health of patients and to define the roles of clinical trial sponsors, administrators and monitors; as well as (iii) under protocols detailing the objectives of the trial, the parameters to be used in monitoring safety and the effectiveness criteria to be evaluated. Each protocol involving testing on U.S. patients and subsequent protocol amendments must be submitted to the FDA as part of the IND.

The FDA may order the temporary or permanent discontinuation of a clinical trial at any time, as a clinical hold or partial clinical hold, or impose other sanctions, if it believes that the clinical trial either is not being conducted in accordance with FDA requirements or presents an unacceptable risk to the clinical trial patients. A clinical hold is an order issued by the FDA to the sponsor to delay a proposed clinical investigation or to suspend an ongoing investigation. A partial clinical hold is a delay or suspension of only part of the clinical work requested under the IND. For example, a specific protocol, or part of a protocol, is not allowed to proceed, while other protocols may do so. No more than 30 days after imposition of a clinical hold or partial clinical hold, the FDA will provide the sponsor a written explanation of the basis for the hold. Following issuance of a clinical hold or partial clinical hold, an investigation may only resume after the FDA has notified the sponsor that the investigation may proceed. The FDA will base that determination on information provided by the sponsor correcting the deficiencies previously cited or otherwise satisfying the FDA that the investigation can proceed.

A sponsor may choose, but is not required, to conduct a foreign clinical study under an IND. When a foreign clinical study is conducted under an IND, all IND requirements must be met unless waived. When the foreign clinical study is not conducted under an IND, the sponsor must ensure that the study complies with certain FDA regulatory requirements in order to use the study as support for an IND or application for marketing approval or licensure. Specifically, the FDA has promulgated regulations governing the acceptance of data from foreign clinical trials not conducted under an IND, establishing that such data from studies will be accepted as support for an IND or application for marketing approval if the study was conducted in accordance with GCP, including review and approval by an independent ethics committee and use of proper procedures for obtaining informed consent from subjects, and the FDA is able to validate the data from the study through an onsite inspection if the FDA deems such inspection necessary. The GCP requirements encompass both ethical and data integrity standards for clinical studies. The FDA’s regulations are intended to help ensure the protection of human subjects enrolled in non-IND foreign clinical trials, as well as the quality and integrity of the resulting data. They further help ensure that non-IND foreign studies are conducted in a manner comparable to that required for IND studies. If a marketing application is based solely on foreign clinical data, the FDA requires that the foreign data be applicable to the U.S. population and U.S. medical practice; the studies must have been performed by clinical investigators of recognized competence; and the FDA must be able to validate the data through an onsite inspection or other appropriate means, if the FDA deems such an inspection to be necessary.

The study protocol and informed consent information for patients in clinical trials must also be submitted to an institutional review board (IRB) representing each institution participating in the clinical trial. The IRB must review and approve the plan for any clinical trial before it commences at that institution, and the IRB must conduct continuing review and reapprove the study at least annually. The IRB must review and approve, among other things, the study protocol and informed consent information to be provided to study subjects. An IRB must operate in compliance with FDA regulations. An IRB may also require the clinical trial at the site to be halted, either temporarily or permanently, for failure to comply with the IRB’s requirements, or may impose other conditions.

Additionally, some trials are overseen by an independent group of qualified experts organized by the trial sponsor, known as a data safety monitoring board or committee. This group provides authorization for whether or not a trial may move forward at designated check points based on access that only the group maintains to available data from the study. Suspension or termination of development during any phase of clinical trials can occur if it is determined that the participants or patients are being exposed to an unacceptable health risk. Other reasons for suspension or termination may be made by us based on evolving business objectives and/or competitive climate.

Information about certain clinical trials must be submitted within specific timeframes to the National Institutes of Health (NIH) for public dissemination on its ClinicalTrials.gov website.Sponsors are also obligated to disclose the results of their clinical trials after completion. Disclosure of the results of these trials can be delayed in certain circumstances for up to two years after the date of completion of the trial.

Clinical trials to support NDAs or BLAs for marketing approval or licensure are typically conducted in three sequential phases, but the phases may overlap. In Phase 1, the drug or biological product is introduced into healthy human subjects or in certain indications such as cancer, into patients with the target disease or condition. The drug is tested in Phase 1 to assess metabolism, pharmacokinetics, pharmacological actions, side effects associated with increasing doses, and, if possible, early evidence of effectiveness. Phase 2 usually involves trials in a limited patient population to determine the effectiveness or potency of the drug or biological product for a particular indication, dosage tolerance and optimum dosage, and to identify common adverse effects and safety risks. If a product candidate demonstrates evidence of effectiveness and an acceptable safety profile in Phase 2 evaluations, Phase 3 trials are conducted. In a Phase 3 trial, the drug or biological product is administered to an expanded patient population, generally at geographically dispersed clinical trial sites, in well-controlled clinical trials to generate enough data to statistically evaluate the efficacy or potency and purity, and safety, of the product for approval or licensure, to establish the overall risk benefit profile of the product, and to provide adequate information for the labeling of the product.

In most cases the FDA requires at least two adequate and well-controlled Phase 3 clinical trials to demonstrate the efficacy or potency of the drug. A single Phase 3 trial with other confirmatory evidence may be sufficient in rare instances, such as where the study is a large multicenter trial demonstrating internal consistency and a statistically very persuasive finding of a clinically meaningful effect on mortality, irreversible morbidity or prevention of a disease with a potentially serious outcome and confirmation of the result in a second trial would be practically or ethically impossible. Post-approval studies, or Phase 4 trials, are often required following initial approval and are intended to gain additional experience and data from treatment of patients in the intended therapeutic indication.

Progress reports detailing the results of the clinical trials conducted under an IND must be submitted at least annually to the FDA and more frequently if serious adverse effects occur. In addition, IND safety reports must be submitted to the FDA for any of the following: serious and unexpected suspected adverse reactions; findings from other studies or animal or in vitro testing that suggest a significant risk in humans exposed to the drug or biological product; and any clinically important increase in the case of a serious suspected adverse reaction over that listed in the protocol or investigator brochure. Phase 1, Phase 2 and Phase 3 clinical trials may not be completed successfully within any specified period, or at all. Furthermore, the FDA or the sponsor may suspend or terminate a clinical trial at any time on various grounds, including a finding that the research subjects are being exposed to an unacceptable health risk. Similarly, an IRB can suspend or terminate approval of a clinical trial at its institution, or an institution it represents, if the clinical trial is not being conducted in accordance with the IRB’s requirements or if the drug or biological product has been associated with unexpected serious harm to patients. The FDA will typically inspect one or more clinical sites to assure compliance with GCP and the integrity of the clinical data submitted in an NDA or BLA.

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

After completion of the required clinical testing, an NDA or BLA is prepared and submitted to the FDA. FDA approval of the NDA or BLA is required before marketing of the product may begin in the United States. The application must include the results of all preclinical, clinical and other testing and a compilation of data relating to the product’s pharmacology, chemistry, manufacture and controls. The cost of preparing and submitting an application is substantial. The submission of most NDAs or BLAs is additionally subject to a substantial application user fee, currently set for fiscal year 2025 at $4,310,002 for applications requiring clinical data, and $2,155,001 for applications not requiring clinical data, and the manufacturer and sponsor under an approved NDA or BLA are also subject to annual program fees, currently set for fiscal year 2025 at $403,889 for each prescription product. These fees are typically increased annually. Sponsors of applications for drugs granted Orphan Drug Designation are exempt from these user fees.

The FDA has 60 days from its receipt of an NDA or BLA to determine whether the application will be accepted for filing based on the agency’s threshold determination that it is sufficiently complete to permit substantive review. The FDA may request additional information rather than accept an NDA or BLA for filing. In this event, the application must be resubmitted with the additional information. The resubmitted application is also subject to review before the FDA accepts it for filing. Once the submission is accepted for filing, the FDA begins an in-depth review. The FDA has agreed to certain performance goals in the review of NDAs and BLAs to encourage timeliness. The FDA intends to review applications for standard review product candidates within ten months of the 60-day filing date; and applications for priority review product candidates within six months. Priority review can be applied to drugs or biological products that the FDA determines treat a serious condition, and if approved, would offer a significant improvement in safety or effectiveness. The FDA determines, on a case-by-case basis, whether the proposed product represents a significant improvement when compared with other available therapies. Significant improvement may be illustrated by evidence of increased effectiveness in the treatment of a condition, elimination or substantial reduction of a treatment limiting product reaction, documented enhancement of patient compliance that may lead to improvement in serious outcomes, and evidence of safety and effectiveness in a new subpopulation. The review process for both standard and priority review may be extended by the FDA for three additional months to consider certain late-submitted information, or information intended to clarify information already provided in the submission.

The FDA is required to refer an application for a novel drug or biological product to an advisory committee for review, evaluation and a recommendation as to whether the application should be approved, or otherwise explain why such referral was not made. An advisory committee is typically a panel that includes clinicians and other experts. The FDA is not bound by the recommendation of an advisory committee, but it generally follows such recommendations.

Before approving an NDA or BLA, the FDA will typically inspect one or more clinical sites to assure compliance with GCP. Additionally, the FDA will inspect the facility or the facilities at which the drug or biological product is manufactured. The FDA will not approve the application unless compliance with cGMPs is satisfactory and the application contains data that provide substantial evidence that the drug is safe and effective, or the biological product is safe, pure and potent, in the indication studied.

After the FDA evaluates the NDA or BLA and accompanying information and the manufacturing facilities, it issues either an approval letter or a complete response letter. An approval letter authorizes commercial marketing of the product with specific prescribing information for specific indications. A complete response letter generally outlines the deficiencies in the submission and may require substantial additional testing, or information, in order for the FDA to reconsider the application. If, or when, those deficiencies have been addressed to the FDA’s satisfaction in a resubmission of the NDA or BLA, the FDA will issue an approval letter. The FDA intends to review such resubmissions in two or six months depending on the type of information included. Even with submission of this additional information, the FDA ultimately may decide that the application does not satisfy the regulatory criteria for approval or licensure.

An approval letter authorizes commercial marketing of the drug or biological product with specific prescribing information for specific indications. As a condition of approval or licensure, the FDA may require a risk evaluation and mitigation strategy (REMS) to help ensure that the benefits of the drug or biological product outweigh the potential risks. REMS can include medication guides, communication plans for healthcare professionals and elements to assure safe use (ETASU). ETASU can include, but are not limited to, special training or certification for prescribing or dispensing, dispensing only under certain circumstances, special monitoring and the use of patient registries. The requirement for a REMS can materially affect the potential market and profitability of the drug or biological product. Moreover, product approval may require substantial post-approval testing and surveillance to monitor the drug’s safety or efficacy. Once granted, product approvals may be withdrawn if compliance with regulatory standards is not maintained or problems are identified following initial marketing.

If the FDA approves or licenses a drug or biological product, it may limit the approved indications for use of the product; require that contraindications, warnings or precautions be included in the product labeling; require that post-approval studies, including Phase 4 clinical trials, be conducted to further assess the drug’s safety after approval or licensure; require testing and surveillance programs to monitor the product after commercialization; or impose other conditions, including distribution restrictions or other risk management mechanisms, including REMS, which can materially affect the potential market and profitability of the product. The FDA may prevent or limit further marketing of a product based on the results of post-market studies or surveillance programs. Changes to some of the conditions established in an approved application, including changes in indications, labeling, or manufacturing processes or facilities, require submission and FDA approval of a new NDA or BLA, or an NDA or BLA supplement before the change can be implemented. An NDA or BLA supplement for a new indication typically requires clinical data similar to that in the original application, and the FDA uses the same procedures and actions in reviewing NDA and BLA supplements as it does in reviewing NDAs and BLAs.

Approval of medicines in the European Union (EU)

In the EU, companies can apply for marketing authorizations under the centralized procedure to the EMA or they can submit their application to the competent authorities in the European Economic Area (EEA) Member States via the decentralized procedure, the national procedure, or the mutual recognition procedure. The centralized procedure is mandatory for certain medicines, such as those produced by biotechnology, orphan medicinal products, advanced therapy medicinal products and those containing a new active substance indicated for the treatment of HIV, AIDS, cancer, neurodegenerative disorders, autoimmune and other immune dysfunctions, viral diseases, or diabetes. The centralized procedure remains optional for medicines containing a new active substance, or which are a significant therapeutic, scientific, or technical innovation or whose authorization would be in the interest of public health. Therefore the centralized procedure remains mandatory for the majority of biological medicinal products.

The marketing authorization granted under the centralized procedure by the EMA will be valid in all EEA Member States. The evaluation of a marketing authorization application by the EMA’s Committee for Medicinal Products for Human Use (CHMP) takes up to 210 “active” days (excluding all “clock stops” for an applicant to address questions by the EMA–there are usually one or two clock stops that last three to six months and one to two months, respectively) but can be extended, should additional information be required by the CHMP. The European Commission makes the final decision to grant a marketing authorization, which is issued within 67 days of receipt of the EMA’s positive opinion. An accelerated assessment procedure of 150 days may be implemented for drugs considered to be of major public health interest. There is also an internal re-examination procedure available in case the applicant disagrees with the CHMP opinion.

Under the mutual recognition procedure, the national marketing authorization holder may submit an application to other EEA Member States. The Member States involved must decide whether to recognize the approval within 90 days of receiving the application. If a Member State does not recognize the marketing authorization, the disputed points are eventually referred to the European Commission, whose decision is binding.

Since the UK has left the EU, it is no longer covered by centralized marketing authorizations. A separate marketing authorization application is required in respect of the UK. The UK government recently reached a new agreement with the EU, the “Windsor Framework,” which replaced the Northern Ireland protocol, according to which, the EU pharmaceutical legal framework acquis continued to apply to Northern Ireland. Since the implementation of the Windsor Framework, medicinal products intended for the UK market including Northern Ireland are now authorized by the MHRA and must bear a “UK only” label. This means that medicinal products placed on the market in Northern Ireland no longer need to be compliant with EU law. These new measures have been implemented as of January 1, 2025. The MHRA has ceased to participate in the assessment of any centralized procedures since January 1, 2021. Since then, the MHRA has launched the Innovative Licensing and Access Pathway (ILAP), a new accelerated assessment procedure for marketing authorization applications that enables eligible products to be authorized in and potentially placed on the UK market faster. On January 1, 2024, the MHRA launched an International Recognition Procedure for marketing authorization applications whereby the MHRA will, when considering such applications, take into account the approval of medicines by trusted reference regulators in Australia, Canada, Switzerland, Singapore, Japan, United States and EU into its own abbreviated assessment.

Clinical trials regulation and data sharing in the EU

In the EU/EEA, all initial clinical trial applications (CTA) must be submitted through the Clinical Trials Information System (CTIS) and ethics approval must be sought from an independent Ethics Committee. Under the EU Clinical Trials Regulation 536/2014, which has been in effect since January 31, 2022, replacing the EU Clinical Trials Directive 2001/20/EC, suspected unexpected serious adverse reactions to the drug being trialed occurring during the clinical trial must be reported via the EudraVigilance database.

In the EU, Transparency Regulation No 1049/ 2001, EMA Policy 0043, EMA Policy 0070, as well as the Clinical Trials Regulation No 536/2014 set out the obligation for sponsors to make publicly available certain information stemming from clinical studies, whether proactively or in response to third party requests. Interested parties based in the EU may submit a request to the EMA to access information included in the marketing authorization application for authorized medicinal products. Commercially confidential information and protected personal data, however, may not be accessed.

The European Health Data Space Regulations (the EHDS Regulations) came into force on March 26, 2025. The aims of the EHDS Regulations are to provide individuals with more control over their electronic health data, enable cross-border sharing of European Health Data (EHD) between national EU healthcare systems and facilitate the sharing of EHD for secondary research purposes. The EHDS Regulations impose new obligations, but also create opportunities for companies engaged in health-related research to share and access health data on a large scale. Although the EHDS Regulations have come into force, key obligations will not apply until March 2029.

Regulatory framework in the UK following Brexit

The UK officially left the EU on January 31, 2020. A transition period during which EU law remained applicable to the UK began on February 1, 2020, and ended on December 31, 2020. The EU regulatory framework for medicinal products in place before the end of the transition period has been preserved in UK domestic legislation as “retained EU law” but the UK may diverge from EU law in the future should it wish to do so. Pursuant to the Northern Ireland Protocol, the EU pharmaceutical legal framework acquis continued to apply in Northern Ireland and medicines could only be placed in the Northern Ireland market if they complied with EU law. The UK government reached a new agreement with the EU, the “Windsor Framework,” which has replaced the Northern Ireland protocol. According to the Windsor Framework, medicinal products intended for the UK market including Northern Ireland are now authorized by the MHRA and must bear a “UK only” label. This means that medicinal products placed on the market in Northern Ireland no longer need to be compliant with EU law. These new measures have been implemented as of January 1, 2025.

Expedited approval pathways

The FDA is authorized to designate certain products for expedited review if they are intended to address an unmet medical need in the treatment of a serious or life-threatening disease or condition. These programs are referred to as Fast Track designation, Breakthrough Therapy designation and Priority Review designation. In addition, Accelerated Approval offers the potential for approval based on a surrogate or intermediate clinical endpoint. In May 2014, the FDA published a final Guidance for Industry titled “Expedited Programs for Serious Conditions Drugs and Biologics,” which provides guidance on the FDA programs that are intended to facilitate and expedite development and review of new drug or biological product candidates as well as threshold criteria generally applicable to concluding that a product candidate is a candidate for these expedited development and review programs.

The FDA may designate a product for Fast Track review if it is intended, whether alone or in combination with one or more other products, for the treatment of a serious or life threatening disease or condition, and nonclinical or clinical data demonstrate the potential to address unmet medical needs for such a disease or condition. For Fast Track products, sponsors may have greater interactions with the FDA and the FDA may initiate review of sections of a Fast Track product’s application before the application is complete. This rolling review may be available if the FDA determines, after preliminary evaluation of clinical data submitted by the sponsor, that a Fast Track product may be effective. The sponsor must also provide, and the FDA must approve, a schedule for the submission of the remaining information and the sponsor must pay applicable user fees. However, the FDA’s review clock for a Fast Track application does not begin until the last section of the application is submitted. In addition, the Fast Track designation may be withdrawn by the FDA if the FDA believes that the designation is no longer supported by data emerging in the clinical trial process.

A product may be designated as a Breakthrough Therapy if it is intended, either alone or in combination with one or more other products, to treat a serious or life threatening disease or condition and preliminary clinical evidence indicates that the product may demonstrate substantial improvement over existing available therapies on one or more clinically significant endpoints, such as substantial treatment effects observed early in clinical development. The FDA may take certain actions with respect to Breakthrough Therapies, including holding meetings with the sponsor throughout the development process; providing timely advice to the product sponsor regarding development and approval; involving more senior staff in the review process; assigning a cross disciplinary project lead for the review team; rolling review; and taking other steps to design the clinical trials in an efficient manner.

Accelerated Approval Pathway

The FDA may grant Accelerated Approval to a drug or biological product for a serious or life threatening condition that provides meaningful therapeutic advantage to patients over available treatments based upon a determination that the drug or biological product has an effect on a surrogate endpoint that is reasonably likely to predict clinical benefit. The FDA may also grant Accelerated Approval for such drug or biological product for such a condition when the product has an effect on an intermediate clinical endpoint that can be measured earlier than an effect on irreversible morbidity or mortality (IMM) and that is reasonably likely to predict an effect on IMM or other clinical benefit, taking into account the severity, rarity or prevalence of the condition and the availability or lack of alternative treatments. Drugs and biological products granted Accelerated Approval must meet the same statutory standards for safety and effectiveness as those granted traditional approval.

For the purposes of Accelerated Approval, a surrogate endpoint is a marker, such as a laboratory measurement, radiographic image, physical sign or other measure that is thought to predict clinical benefit but is not itself a measure of clinical benefit. Surrogate endpoints can often be measured more easily or more rapidly than clinical endpoints. An intermediate clinical endpoint is a measurement of a therapeutic effect that is considered reasonably likely to predict the clinical benefit of a drug or biological product, such as an effect on IMM. The FDA has limited experience with Accelerated Approvals based on intermediate clinical endpoints, but has indicated that such endpoints generally may support Accelerated Approval where the therapeutic effect measured by the endpoint is not itself a clinical benefit and basis for traditional approval, if there is a basis for concluding that the therapeutic effect is reasonably likely to predict the ultimate clinical benefit of a drug or biological product.

The Accelerated Approval Pathway is most often used in settings in which the course of a disease is long and an extended period of time is required to measure the intended clinical benefit of a drug or biological product, even if the effect on the surrogate or intermediate clinical endpoint occurs rapidly. Thus, Accelerated Approval has been used extensively in the development and approval of drugs and biological products for treatment of a variety of cancers in which the goal of therapy is generally to improve survival or decrease morbidity and the duration of the typical disease course requires lengthy and sometimes large trials to demonstrate a clinical or survival benefit.

The Accelerated Approval Pathway is contingent on a sponsor’s agreement to conduct, in a diligent manner, additional post-approval confirmatory studies to verify and describe the product’s clinical benefit. As a result, a drug or biological product candidate approved on this basis is subject to rigorous post-marketing compliance requirements, including the completion of Phase 4 or post-approval clinical trials to confirm the effect on the clinical endpoint. Failure to conduct required post-approval studies, or confirm a clinical benefit during post-marketing studies, would allow the FDA to withdraw the drug or biological product from the market on an expedited basis, and under the Food and Drug Omnibus Reform Act of 2022, the FDA has increased authority to expedite withdrawals. In addition, all promotional materials for drugs and biological products approved under accelerated regulations are subject to prior review by the FDA.

The EU and UK operate accelerated evaluation and assessment schemes, which include, at EU level, Priority Medicines (PRIME) scheme and, at UK level, the Early Access to Medicines Scheme (EAMS), which may be granted in exceptional cases, often when there is unmet medical need for a life-threatening or serious debilitating condition and existing data show a positive benefit/risk balance that means the medicinal product is of a major public health interest. The CHMP of the EMA or the MHRA (or other national competent authority) will make this determination on a case-by-case basis and subject to meeting eligibility criteria. Accelerated assessment takes place within 150 days. Other regulatory facilitations for these pathways include additional scientific advice at key development milestones and frequent guidance and discussions throughout the approval process. In the UK, the MHRA has launched the Innovative Licensing and Access Pathway (ILAP), a new accelerated assessment procedure for marketing authorization applications that enables companies to enter the UK market faster, available since January 1, 2021. On January 1, 2024, the MHRA launched an International Recognition Procedure for Great Britain (England, Scotland and Wales) marketing authorization applications whereby the MHRA will, when considering such applications, recognize the approval of medicines by trusted reference regulators in Australia, Canada, Switzerland, Singapore, Japan, United States and EU following its own abbreviated assessment.

Orphan drugs

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