regn-20251231

UNITED STATES

SECURITIES AND EXCHANGE COMMISSION

Washington, D.C. 20549

FORM 10-K

(Mark One)

For the fiscal year ended December 31, 2025

For the transition period from __________ to __________

REGENERON PHARMACEUTICALS, INC.

(Exact name of registrant as specified in its charter)

(Address of principal executive offices, including zip code)

(914) 847-7000

(Registrant's telephone number, including area code)

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

Title of each class Trading Symbol Name of each exchange on which registered

Common Stock - par value $.001 per share REGN NASDAQ Global Select Market

Securities registered pursuant to section 12(g) of the Act: None

Class of Common Stock Number of Shares

DOCUMENTS INCORPORATED BY REFERENCE

REGENERON PHARMACEUTICALS, INC.

ANNUAL REPORT ON FORM 10-K

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Page Numbers

PART I

Item 1. Business 2

Item 1A. Risk Factors 36

Item 1B. Unresolved Staff Comments 70

Item 1C. Cybersecurity 71

Item 2. Properties 71

Item 3. Legal Proceedings 72

Item 4. Mine Safety Disclosures 72

PART II

Item 6. [Reserved] 74

Item 7A. Quantitative and Qualitative Disclosures About Market Risk 88

Item 8. Financial Statements and Supplementary Data 89

Item 9A. Controls and Procedures 89

Item 9B. Other Information 90

Item 9C. Disclosure Regarding Foreign Jurisdictions that Prevent Inspections 90

PART III

Item 10. Directors, Executive Officers and Corporate Governance 90

Item 11. Executive Compensation 90

Item 14. Principal Accountant Fees and Services 90

PART IV

Item 15. Exhibits and Financial Statement Schedules 91

SIGNATURE PAGE 95

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PART I

Item 1. Business

This Annual Report on Form 10-K contains forward-looking statements that involve risks and uncertainties relating to future events and the future performance of Regeneron Pharmaceuticals, Inc. (where applicable, together with its subsidiaries, "Regeneron," "Company," "we," "us," and "our"), and actual events or results may differ materially from these forward-looking statements. Words such as "anticipate," "expect," "intend," "plan," "believe," "seek," "estimate," variations of such words, and similar expressions are intended to identify such forward-looking statements, although not all forward-looking statements contain these identifying words. These statements concern, and these risks and uncertainties include, among others:

•competing products and product candidates (including biosimilar products) that may be superior to, or more cost effective than, products marketed or otherwise commercialized by Regeneron and/or its collaborators or licensees (collectively, "Regeneron's Products") and product candidates being developed by Regeneron and/or its collaborators or licensees (collectively, "Regeneron's Product Candidates");

•uncertainty of the utilization, market acceptance, and commercial success of Regeneron's Products and Regeneron's Product Candidates and the impact of studies (whether conducted by Regeneron or others and whether mandated or voluntary) or recommendations and guidelines from governmental authorities and other third parties or other factors beyond Regeneron's control on the commercial success of Regeneron's Products and Regeneron's Product Candidates;

•the nature, timing, and possible success and therapeutic applications of Regeneron's Products and Regeneron's Product Candidates and research and clinical programs now underway or planned, including without limitation those discussed or referenced in this report, Regeneron's and its collaborators' earlier-stage programs, and the use of human genetics in Regeneron's research programs;

•the likelihood and timing of achieving any of our anticipated development milestones referenced in this report;

•safety issues resulting from the administration of Regeneron's Products and Regeneron's Product Candidates in patients, including serious complications or side effects in connection with the use of Regeneron's Products and Regeneron's Product Candidates in clinical trials;

•the likelihood, timing, and scope of possible regulatory approval and commercial launch of Regeneron's Product Candidates and new indications for Regeneron's Products, including without limitation those discussed or referenced in this report;

•the extent to which the results from the research and development programs conducted by us and/or our collaborators may be replicated in other studies and/or lead to advancement of product candidates to clinical trials, therapeutic applications, or regulatory approval;

•ongoing regulatory obligations and oversight impacting Regeneron's Products, research and clinical programs, and business, including those relating to patient privacy;

•determinations by regulatory and administrative governmental authorities which may delay or restrict our ability to continue to develop or commercialize Regeneron's Products and Regeneron's Product Candidates;

•our ability to manufacture and manage supply chains for multiple products and product candidates and risks associated with tariffs and other trade restrictions;

•the ability of our collaborators, suppliers, or other third parties (as applicable) to perform manufacturing, filling, finishing, packaging, labeling, distribution, and other steps related to Regeneron's Products and Regeneron's Product Candidates;

•the availability and extent of reimbursement or copay assistance for Regeneron's Products from third-party payors and other third parties, including private payor healthcare and insurance programs, health maintenance organizations, pharmacy benefit management companies, and government programs such as Medicare and Medicaid;

•coverage and reimbursement determinations by such payors and other third parties and new policies and procedures adopted by such payors and other third parties;

•changes to drug pricing regulations and requirements and our drug pricing strategy;

•other changes in laws, regulations, and policies affecting the healthcare industry;

•the costs of developing, producing, and selling products or unanticipated expenses;

•our ability to meet any of our financial projections or guidance and changes to the assumptions underlying those projections or guidance;

•the potential for any license or collaboration agreement, including our agreements with Sanofi and Bayer (or their respective affiliated companies, as applicable), to be cancelled or terminated;

•the impact of public health outbreaks, epidemics, or pandemics on our business; and

•risks associated with litigation and other proceedings and government investigations relating to the Company and/or its operations (including without limitation those described in Note 16 to our Consolidated Financial Statements included in this report), risks associated with intellectual property of other parties and pending or future litigation relating thereto (including without limitation the patent litigation and other related proceedings described further in Note 16 to our Consolidated Financial Statements included in this report), the ultimate outcome of any such proceedings and investigations, and the impact any of the foregoing may have on our business, prospects, operating results, and financial condition.

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These statements are made based on management's current beliefs and judgment, and the reader is cautioned not to rely on any such statements. In evaluating such statements, shareholders and potential investors should specifically consider the various factors identified under Part I, Item 1A. "Risk Factors," which could cause actual events and results to differ materially from those indicated by such forward-looking statements. We do not undertake any obligation to update (publicly or otherwise) any forward-looking statement, whether as a result of new information, future events, or otherwise.

General

Regeneron Pharmaceuticals, Inc. is a fully integrated biotechnology company that invents, develops, manufactures, and commercializes medicines for people with serious diseases. Our products and product candidates in development are designed to help patients with eye diseases, allergic and inflammatory diseases, cancer, cardiovascular and metabolic diseases, neurological diseases, hematologic conditions, infectious diseases, and rare diseases.

Our core business strategy is to maintain a strong foundation in scientific research and drug development using our proprietary technologies, and to build on that foundation with our clinical development, manufacturing, and commercial capabilities. Our objective is to continue to advance as an integrated, multi-product biotechnology company that provides patients and medical professionals with important medicines for preventing and treating human diseases.

Selected financial information is summarized as follows:

Year Ended December 31,

For purposes of this report, references to our products encompass products commercialized by us and/or our collaborators or licensees and references to our product candidates encompass product candidates in development by us and/or our collaborators or licensees (in the case of collaborated or licensed products or product candidates under the terms of the applicable collaboration or license agreements), unless otherwise stated or required by the context.

Products

Products that have received marketing approval are summarized in the table below. Certain products have also received marketing approval in countries outside the United States, European Union ("EU"), or Japan.

Product Disease Territory

U.S. EU Japan

Diabetic macular edema ("DME") a a a

Diabetic retinopathy ("DR") a

Macular edema following retinal vein occlusion ("RVO") a a

EYLEA® (aflibercept) Injection(a) wAMD a a a

DME a a a

DR a

RVO a a a

Myopic choroidal neovascularization ("mCNV") a a

Neovascular glaucoma ("NVG") a

Retinopathy of prematurity ("ROP") a a a

Asthma (in adults and adolescents) a a a

Asthma (in pediatrics 6–11 years of age) a a a

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Product (continued) Disease Territory

U.S. EU Japan

CRSwNP (in adolescents) a

Chronic obstructive pulmonary disease ("COPD") a a a

Eosinophilic esophagitis ("EoE") (in patients aged 1 year and older) a a

Prurigo nodularis a a a

Chronic spontaneous urticaria ("CSU") (in adults and adolescents) a a a

Bullous pemphigoid a

Metastatic or locally advanced basal cell carcinoma ("BCC") a a

Metastatic or locally advanced cutaneous squamous cell carcinoma ("CSCC") a a

Adjuvant CSCC a a

Metastatic or recurrent second-line cervical cancer a a

Hypercholesterolemia a a

Homozygous familial hypercholesterolemia ("HoFH") a

Kevzara® (sarilumab) Injection(b) Rheumatoid arthritis ("RA") a a a

Polymyalgia rheumatica ("PMR") a a

Polyarticular juvenile idiopathic arthritis ("pJIA") a a

OrdsponoTM (odronextamab) Follicular lymphoma ("FL") a

Diffuse large B-cell lymphoma ("DLBCL") a

LynozyficTM (linvoseltamab) Relapsed/refractory multiple myeloma a a

Recurrent pericarditis (in adults and adolescents) a

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(b) In collaboration with Sanofi

(e) Kiniksa is responsible for the development and commercialization of ARCALYST

(f) Sanofi is responsible for the development and commercialization of ZALTRAP

The table below includes net product sales of Regeneron-discovered products. Such net product sales are recorded by us or others, as further described in the footnotes to the table. We believe the information in the table is useful to investors as it demonstrates our pipeline productivity and our ability to innovate, discover, and develop new products, and bring those products to market either alone or based on contractual arrangements with other parties, which has a direct impact on our results of operations and financial condition. The table also shows the degree to which we, a collaborator, and/or a licensee is currently commercializing the products discovered by Regeneron. In addition, this information allows management and investors to assess the commercial trends and developments impacting Regeneron-discovered products. In arrangements where our collaborator or licensee is currently commercializing such products and is recording net product sales as a result, the net product sales shown in the table also are an important metric for management's review and assessment of (i) the revenues we record for our share of profits and/or royalties from such sales and (ii) the impact of our obligation to supply commercial product to certain of these collaborators or licensees.

Year Ended December 31,

(In millions) U.S. ROW(f) Total U.S. ROW Total U.S. ROW Total

(f) Rest of world ("ROW")

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Programs in Clinical Development

Product candidates in Phase 2 and Phase 3 clinical development, which are being developed by us and/or our collaborators, are summarized in the table below.

There are numerous uncertainties associated with drug development, including uncertainties related to safety and efficacy data from each phase of drug development (including any post-approval studies), uncertainties related to the enrollment and performance of clinical trials, changes in regulatory requirements, changes to drug pricing and reimbursement regulations and requirements, and changes in the competitive landscape affecting a product candidate. The planning, execution, and results of our clinical programs are significant factors that can affect our operating and financial results.

Refer to Part I, Item 1A. "Risk Factors" for a description of risks and uncertainties that may affect our clinical programs. Any of such risks and uncertainties may, among other matters, negatively impact the development timelines set forth in the table below.

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Ophthalmology

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Immunology & Inflammation

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Solid Organ Oncology

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VidutolimodImmune activator targeting TLR9

REGN5668(p)Bispecific antibody targeting MUC16 and CD28 –Ovarian cancer

Marlotamig (REGN7075)Bispecific antibody targeting EGFR and CD28 –Solid tumors

Hematology

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REGN7257Antibody to IL2Rg –Discontinued study in aplastic anemia

REGN7999Antibody to TMPRSS6 –Iron overload in beta-thalassemia

Internal Medicine/Neurology/Rare Diseases

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ALN-ANG3(k)(r)RNAi therapeutic targeting ANGPTL3 –Diabetic kidney disease

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(a) In collaboration with Bayer outside the United States

(b) In collaboration with Sanofi

(d) FDA granted Breakthrough Therapy designation for one or more indications

(e) FDA granted Fast Track designation for one or more indications

(f) Sanofi is entitled to receive royalties on sales of the product

(i) BioNTech's BNT116 is an mRNA cancer vaccine

(j) In collaboration with Intellia

(k) Alnylam is entitled to receive royalties on sales of the product

(n) Studied in combination with semaglutide with and without garetosmab

(p) Studied in combination with ubamatamab or fianlimab

(q) Geographic atrophy also studied with cemdisiran monotherapy

(r) Studied as monotherapy and in combination with Evkeeza (evinacumab)

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Additional Information - Clinical Development Programs

EYLEA HD

In August 2025, the FDA extended the target action dates for the Company's FDA applications for EYLEA HD (pre-filled syringe, every-four-week dosing, and for the treatment of RVO). The delay resulted from observations from a July 2025 FDA general site inspection (not specific to EYLEA HD) at Catalent Indiana, LLC ("Catalent"), part of Novo Nordisk A/S, the manufacturing filler in the EYLEA HD BLA. The FDA extended the review periods after determining that the information submitted by the manufacturing filler in August 2025 to address the observations constituted a major amendment to each regulatory application.

In October 2025, the Company was notified by Catalent that they received an official action indicated ("OAI") letter from the FDA citing unresolved issues related to a July 2025 FDA general site inspection. On October 27, 2025, the FDA issued a CRL for the pre-filled syringe sBLA. The sole approvability issue cited in the CRL relates to unresolved inspection findings at Catalent. In December 2025, the Company submitted a regulatory application seeking approval of the EYLEA HD pre-filled syringe using a new manufacturer. The application has been accepted for review, a standard pre-licensing inspection has been scheduled, and an FDA decision on the Company's filing is expected in the second quarter of 2026.

In November 2025, the FDA approved EYLEA HD for the treatment of patients with RVO and for an every 4-week dosing option across approved indications. In addition, in December 2025, the FDA approved the addition of a new manufacturer to fill vials for EYLEA HD.

Itepekimab

In May 2025, the Company and Sanofi announced that a Phase 3 trial, AERIFY-1, in adults who were former smokers with inadequately controlled COPD met the primary endpoint of significantly reducing moderate or severe acute exacerbations by 27% compared to placebo at week 52, a clinically meaningful benefit. A second Phase 3 trial, AERIFY-2, did not meet the same primary endpoint, although a benefit was seen earlier in the trial. The safety profile of itepekimab observed in the Phase 3 trials was consistent with prior clinical trials. The Company and Sanofi are evaluating next steps.

Fianlimab

In April 2025, a pre-planned interim analysis was conducted on two ongoing Phase 2/3 studies evaluating the combination of fianlimab and cemiplimab in first-line advanced NSCLC. Due to limited follow-up, the Phase 2 portion of the studies will continue unchanged until additional data are available. The next analyses for these studies are expected in the first half of 2026, at which time a decision whether to advance to Phase 3 is expected to be made. No new safety signals were observed in either study.

Ordspono (odronextamab)

On July 30, 2025, the FDA issued a CRL for the BLA for odronextamab in relapsed/refractory follicular lymphoma after two or more lines of systemic therapy, which was also impacted by the Catalent Indiana LLC site inspection (as described in the "EYLEA HD" section above).

Descriptions of Marketed Products Studied in Additional Indications and Product Candidates in Late-Stage Clinical Development

EYLEA HD (aflibercept) 8 mg

EYLEA HD is a soluble fusion protein that acts as a vascular endothelial growth factor ("VEGF") inhibitor. Through a novel formulation, it is designed to deliver a concentrated dose of aflibercept to block VEGF-A and PLGF and inhibit the growth of new blood vessels and decrease vascular permeability to treat various retinal diseases, including wAMD, DME, DR, and RVO.

Dupixent (dupilumab)

Dupixent is a fully human monoclonal antibody that inhibits signaling of the IL-4 and IL-13 pathways, and is not an immunosuppressant. IL-4 and IL-13 are key and central drivers of the type 2 inflammation that play a major role in atopic dermatitis, asthma, CRSwNP, COPD, EoE, prurigo nodularis, CSU, bullous pemphigoid, and potentially other chronic allergic and inflammatory diseases.

Kevzara (sarilumab)

Kevzara is a fully human monoclonal antibody that binds specifically to the IL-6 receptor and inhibits IL-6-mediated signaling. IL-6 is an immune system protein produced in increased quantities in patients with inflammatory diseases such as RA and has been associated with disease activity, joint destruction, and other systemic problems.

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Itepekimab

Itepekimab is an investigational, fully human monoclonal antibody that inhibits IL-33, a protein that is believed to play a key role in inflammation in COPD and CRSwNP.

REGN5713-5715

REGN5713-5715 is an investigational combination of two fully human monoclonal antibodies designed to treat allergic inflammatory conditions caused by the allergen Bet v 1, which is the main allergen responsible for birch pollen allergies. Birch pollen allergy is one of the most common causes of seasonal allergies that occur in the spring, and is also believed to trigger "oral allergy syndrome" food reactions to related allergens found in nuts and fruits such as apples, pears, and cherries.

REGN1908-1909

REGN1908-1909 is an investigational combination of two fully human monoclonal antibodies that is designed to specifically bind and block the Fel d 1 allergen, thus preventing it from binding and triggering the endogenous antibodies that cause allergies (i.e., immunoglobulin E antibodies). Cat allergy is primarily caused by exposure to Fel d 1, the major allergen in cat dander produced by all cats.

Libtayo (cemiplimab)

Libtayo is a fully human monoclonal antibody targeting the immune checkpoint receptor PD-1 on T-cells. The PD-1/PD-L1 immune checkpoint pathway is a well-known mechanism by which cancers evade immune destruction. Regeneron is studying Libtayo as a monotherapy and in combination with either conventional or novel therapeutic approaches in various solid tumors and blood cancers. It is also being studied in combination with proprietary anti-cancer assets of other companies. Libtayo has also been approved by regulatory authorities in a number of cancer indications, including as a treatment for advanced NSCLC, BCC, CSCC, and cervical cancer, and as an adjuvant treatment for patients with CSCC with a high risk of recurrence after surgery and radiation.

Fianlimab

Fianlimab is an investigational, fully human monoclonal antibody targeting the immune checkpoint receptor LAG-3 on T-cells. In melanoma and NSCLC, LAG-3 expression in the tumor microenvironment may be associated with therapeutic resistance to PD-1 inhibitors. Fianlimab is being investigated in combination with Libtayo to determine whether concurrent blockade of LAG-3 and PD-1 can help overcome this resistance and release the brakes on T-cell activation.

Pozelimab

Pozelimab is a fully human monoclonal antibody designed to block complement factor C5 in order to treat diseases mediated by abnormal complement pathway activity, and is approved by the FDA for CHAPLE. Pozelimab is being studied in investigational combinations with an investigational small interfering RNA ("siRNA") therapy, cemdisiran, in PNH and geographic atrophy.

Cemdisiran

Cemdisiran is an investigational siRNA therapy that reduces circulating levels of C5. Cemdisiran, as a monotherapy and in combination with pozelimab (C5 antibody), is being evaluated in trials for complement-mediated disorders, including myasthenia gravis, PNH, and geographic atrophy.

Ordspono (odronextamab)

Ordspono is a bispecific monoclonal antibody designed to bridge CD20 on cancer cells with CD3-expressing T cells to facilitate local T-cell activation and cancer-cell killing. We are studying Ordspono in several types of B-cell non-Hodgkin lymphoma, including in frontline settings.

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Lynozyfic (linvoseltamab)

Lynozyfic is a bispecific monoclonal antibody designed to bind to CD3 while also binding and bridging T-cells to the BCMA protein on multiple myeloma cells. This may help to activate T-cells via their CD3 receptors and trigger targeted, T-cell mediated killing of multiple myeloma. Lynozyfic has been approved by regulatory authorities for relapsed or refractory multiple myeloma, and continues to be studied in multiple lines and settings of multiple myeloma.

Nex-z

Nex-z is an investigational CRISPR-based therapy to be systemically delivered to edit genes inside the human body and is being studied as a treatment for ATTR amyloidosis. ATTR amyloidosis is a progressive and fatal disorder resulting from deposition of insoluble amyloid fibrils into multiple organs and tissues leading to systemic failure. Delivered with in vivo technology, nex-z offers the possibility of halting and reversing the disease by driving a deep, consistent, and potentially lifelong reduction in transthyretin ("TTR") protein after a single dose.

REGN7508 and REGN9933

We are advancing a robust factor XI program to assess two mechanistically-distinct antibodies, REGN7508 (catalytic domain) and/or REGN9933 (A2 domain), across a variety of indications. These two antibodies were prospectively designed to have distinct profiles – with one designed to provide stronger anticoagulation and the other offering a lower risk of bleeding – potentially allowing physicians to tailor anticoagulation therapy for patients with different risk profiles.

Garetosmab

Garetosmab is an investigational, fully human monoclonal antibody that binds to and neutralizes Activin A, which drives the abnormal bone formation that is the main pathology of the ultra-rare genetic disorder FOP. This abnormal bone formation in soft tissue outside of the normal skeleton, a process known as heterotopic ossification, leads to loss of mobility and premature death in FOP patients. Garetosmab is being investigated to determine whether it can help reduce and/or prevent the formation of heterotopic bone lesions by neutralizing the Activin A protein.

Mibavademab

Mibavademab is an investigational, fully human monoclonal antibody that binds to and activates the leptin receptor, which modulates the control of food intake, energy expenditure, and glucose/lipid metabolism. We are studying mibavademab as a potential treatment for generalized lipodystrophy.

DB-OTO

DB-OTO is an investigational cell-selective, dual AAV vector gene therapy designed to provide durable, physiological hearing to individuals with profound, congenital hearing loss caused by variants of the otoferlin gene. The treatment aims to deliver a working copy of the otoferlin gene to replace the non-functional otoferlin protein using a modified, non-pathogenic virus that is delivered via an infusion into the cochlea under general anesthesia (similar to the procedure used for cochlear implantation). In this gene therapy, the newly introduced otoferlin gene is under the control of a proprietary cell-specific Myo15 promoter, which is intended to restrict expression only to hair cells that normally express otoferlin.

Other Programs

Our preclinical research programs include the areas of oncology/immuno-oncology, angiogenesis, ophthalmology, metabolic and related diseases, muscle diseases and disorders, inflammation and immune diseases, bone and cartilage, pain and neurobiology, auditory conditions, enzyme replacement therapy, cardiovascular diseases, infectious diseases, and diseases related to aging. These preclinical research programs include both rare diseases and those involving broader populations.

Research and Development Technologies

Many proteins that play an important role in biology and disease are secreted by cells or located on the cell surface. Moreover, cells communicate through secreted factors and surface molecules. Our scientists have developed two different technologies to make protein therapeutics that potently and specifically block, activate, or inhibit the action of specific cell surface or secreted molecules. The first technology fuses receptor components to the constant region of an antibody molecule to make a class of drugs we call "Traps." EYLEA HD, EYLEA, ZALTRAP, and ARCALYST are drugs generated using our Trap technology. VelociSuite® is our second technology platform, which is used for discovering, developing, and producing fully human antibodies that can address both secreted and cell-surface targets. We also leverage VelociSuiteto produce new classes of bispecific antibodies, antibody-protein fusions, and antibody conjugates. Additionally, we use genetic medicine platforms as complementary approaches to these core technologies to potentially treat or cure diseases.

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VelociSuite

VelociSuite consists of VelocImmune®, VelociGene®, VelociMouse®, VelociMab®, Veloci-Bi®, VelociT®, VelociHum®, and other related technologies. The VelocImmune mouse platform is utilized to produce fully human antibodies. VelocImmune was generated by leveraging our VelociGene technology (see below), in a process in which six megabases of mouse immunoglobulin gene loci were replaced, or "humanized," with corresponding human immunoglobulin gene loci. VelocImmune mice can be used efficiently to generate fully human antibodies to targets of therapeutic interest. VelocImmune and our entire VelociSuite offer the potential to increase the speed and efficiency through which human antibody therapeutics may be discovered and validated, thereby improving the overall efficiency of our early-stage drug development activities. We are utilizing the VelocImmune technology to produce our next generation of therapeutic antibody drug candidates for preclinical and clinical development.

Our VelociGene platform allows custom and precise manipulation of very large sequences of DNA to produce highly customized alterations of a specified target gene, or genes, and accelerates the production of knock-out and transgenic expression models. In producing knock-out models, a color or fluorescent marker may be substituted in place of the actual gene sequence, allowing for high-resolution visualization of precisely where the gene is active in the body during normal body functioning as well as in disease processes. For the optimization of preclinical development and pharmacology programs, VelociGene offers the opportunity to humanize targets by replacing the mouse gene with the human homolog or variants thereof. Thus, VelociGene allows scientists to rapidly identify the physical and biological effects of deleting or over-expressing the target gene, as well as to characterize and test potential therapeutic molecules.

Our VelociMouse technology platform allows for the direct and immediate generation of genetically altered mice from embryonic stem cells ("ES cells"), thereby avoiding the lengthy process involved in generating and breeding knockout mice from chimeras. Mice generated through this method are normal and healthy and exhibit a 100% germ-line transmission. Furthermore, mice developed using our VelociMouse technology are suitable for direct phenotyping or other studies.

We have also developed our VelociMab platform for the rapid screening of antibodies and rapid generation of expression cell lines for our Traps and our VelocImmune human antibodies.

We have utilized our VelociSuite technologies to develop a class of potential drug candidates, known as bispecific antibodies. Veloci-Bi allows for the generation of full-length bispecific antibodies similar to native antibodies that are amenable to production by standard antibody manufacturing techniques, and are likely to have favorable antibody-like pharmacokinetic properties. In the area of immunotherapies in oncology, we are exploring the use of bispecific antibodies that target tumor antigens and the CD3 receptor on T-cells to harness the oncolytic properties of T-cells. We are exploring additional indications and applications for our bispecific technologies, including CD28 and 4-1BB costimulatory bispecifics. We are also exploring a variety of alternative antibody formats (AltibodiesTM) that can bring binding partners together in restrained geometries.

The VelociT mouse extends our research and drug discovery capabilities into cell-mediated immunity and therapeutic T-cell receptors ("TCRs") for oncology and other indications. VelociT was developed by using our VelociGene technology to humanize genes encoding TCRα and TCRβ variable sequences, CD4 and CD8 co-receptors, β2m, and class-I and -II major histocompatibility complexes. As a result, VelociT mice can be utilized to produce fully human TCRs, providing for customized modeling of T-cell function in different diseases and a powerful platform for the discovery of unique TCR-based therapies. We are also able to produce antibodies that recognize intracellular peptides bound in the groove of human leukocyte antigen ("HLA"), enabling the targeting of intracellular proteins in cancer cells.

VelociHum is our immunodeficient mouse platform that can be used to accurately test human therapeutics against human immune cells and to study human tumor models. Through genetic humanizations, VelociHum mice have been optimized to allow for better development of human immune cells in vivo, as well as to allow for engraftment of primary patient-derived tumors that do not take in other commercially available mice.

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Regeneron Genetics Center®

Regeneron Genetics Center LLC (RGC®), a wholly owned subsidiary of Regeneron Pharmaceuticals, Inc., leverages de-identified clinical, genomic, proteomic, and other types of molecular data from properly consented human volunteers from around the world to identify medically relevant associations in a blinded fashion designed to preserve a patient's privacy while uncovering the unique characteristics of their health and wellness. The objective of RGC is to expand the use of human genetics for discovering and validating genetic factors that cause or influence a range of diseases where there are major unmet medical needs, with the prospect of improving the drug discovery and development process and to advance innovation in clinical care design. RGC is undertaking multiple collaborative approaches to study design and implementation, including large population-based efforts that engage study participants to more discrete disease specific and founder populations with data on strategic phenotypes of interest. RGC utilizes laboratory automation and innovative approaches to cloud computing to achieve high-quality throughput, attaining over 3 million samples sequenced to date.

In January 2025, it was announced that RGC was selected by UK Biobank consortium members to complete proteomic assay data generation for the UK Biobank Pharma Proteomics Project.

In January 2025, RGC entered into an agreement with Truveta Inc. pursuant to which RGC will sequence exomes and conduct genotyping and imputation of up to ten million de-identified consented volunteers using biospecimens provided by Truveta health system members across the United States. In addition, central to the ongoing work of RGC is the portfolio of collaborations with over 150 academic and clinical collaborators around the world, including the University of Colorado, Geisinger Health System, Mayo Clinic, University of Pennsylvania, UCLA Medical Center, UK Biobank, University of Oxford, and the University of Cambridge. These collaborations provide access to biological samples and associated phenotype data from properly consented patient volunteers for purposes of genomic research. RGC undertakes genetic sequencing of these samples to create a unique resource of de-identified genetic data and associated phenotype data for research. Furthermore, RGC has deployed bulk RNA sequencing, whole genome sequencing, and an O-LINK proteomic assay to complement whole exome sequencing and genotyping. In addition, RGC leverages organoid models, siRNA, and CRISPR knockout models to validate genetic associations that lead to new therapeutic targets. RGC continues to publish results from its research efforts in journals and publications in partnership with its collaborators to advance the field of genomics.

These efforts at RGC have led to the identification of more than 40 novel genetic targets. Through our Regeneron Genetics Medicines initiative, we are currently advancing many of these targets using either our VelociSuite technologies or other technologies, such as siRNA gene silencing, genome editing, and targeted viral-based gene delivery and expression. See the "Collaboration, License, and Other Agreements" section below for descriptions of our agreements with Alnylam Pharmaceuticals, Inc. and Intellia Therapeutics, Inc.

Collaboration, License, and Other Agreements

Sanofi

We are collaborating with Sanofi on the global development and commercialization of Dupixent, Kevzara, and itepekimab. Under the terms of the collaboration, Sanofi is generally responsible for funding 80% to 100% of agreed-upon development expenses as incurred. We are obligated to reimburse Sanofi for 30% to 50% of development expenses that were funded by Sanofi (i.e., "development balance") based on our share of collaboration profits; however, we are only required to apply 20% of our share of profits from the collaboration each calendar quarter to reimburse Sanofi for these development expenses. As of December 31, 2025, the total amount of our contingent reimbursement obligation to Sanofi in connection with the development balance was approximately $595 million.

Under our collaboration agreement, Sanofi records product sales for commercialized products, and we have the right to co-commercialize such products on a country-by-country basis. We co-commercialize Dupixent in the United States and in certain countries outside the United States. We supply certain commercial bulk product to Sanofi. We and Sanofi equally share profits from sales within the United States, and share profits outside the United States on a sliding scale based on sales starting at 65% (Sanofi)/35% (us) and ending at 55% (Sanofi)/45% (us).

Bayer

We and Bayer are parties to a license and collaboration agreement for the global development and commercialization of EYLEA 8 mg and EYLEA outside the United States. Agreed-upon development expenses incurred by the Company and Bayer are generally shared equally. Bayer is responsible for commercialization activities outside the United States, and the companies share equally in profits from such sales.

We are obligated to reimburse Bayer for 50% of the development expenses that it has incurred under the agreement from our share of the collaboration profits. The reimbursement payment in any quarter will equal 5% of the then outstanding repayment

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obligation, but never more than our share of the collaboration profits in the quarter unless we elect to reimburse Bayer at a faster rate.

Within the United States, we retain exclusive commercialization rights and are entitled to all profits from such sales.

Alnylam

We and Alnylam Pharmaceuticals, Inc. are parties to a collaboration to discover, develop, and commercialize RNAi therapeutics for a broad range of diseases by addressing therapeutic disease targets expressed in the eye and central nervous system, in addition to a select number of targets expressed in the liver.

For each target nominated, we provide Alnylam with a specified amount of funding at program initiation and at lead candidate designation. Under the terms of the collaboration, the parties perform discovery research until designation of lead candidates. Following designation of a lead candidate, the parties may further advance such lead candidate under either a co-development and co-commercialization collaboration agreement ("Co-Co Collaboration Agreement") or a license agreement. The target nomination period of the collaboration agreement ends in May 2026.

For CNS programs and liver programs, under a Co-Co Collaboration Agreement, the party designated as the lead party will lead development and commercialization of the program and the parties will split profits and share costs equally, subject to certain co-funding opt-outs at specified clinical trial phases or under other conditions.

We have also entered into various license agreements with Alnylam, with us as the licensee, including for cemdisiran as a monotherapy and for a combination consisting of cemdisiran and pozelimab. Under a license agreement, the lead party is designated as the licensee and has the right to develop and commercialize the product under such program. The licensee will be responsible for its own expenses incurred. The licensee will pay to the licensor certain development and/or commercialization milestone payments, as well as tiered royalty payments to the licensor based on the aggregate annual sales of the product.

Intellia

We and Intellia Therapeutics, Inc. are parties to a license and collaboration agreement to advance CRISPR/Cas9 gene-editing technology for in vivo therapeutic development, including therapies focused on neurological and muscular diseases. We have the right to select targets under the license and collaboration agreement until April 2026.

Intellia leads the design of the editing methodology, we lead the design of the targeted viral vector delivery approach, and the parties share costs. Each company has the opportunity to lead potential development and commercialization of product candidates for a target, and the company that is not leading development and commercialization will have the option to enter into a co-development and co-commercialization agreement for the target.

Nex-z, which is in clinical development, is subject to a co-development and co-commercialization arrangement pursuant to which Intellia leads development activities and the parties share development expenses 75% (Intellia)/25% (us). If nex-z is commercialized, Intellia will lead commercialization activities and we will share in 25% of any profits or losses.

Hansoh

In July 2025, our license agreement with Hansoh Pharmaceuticals Group Company Limited to acquire development and commercial rights outside of mainland China, Hong Kong, and Macau for HS-20094 (a dual GLP-1/GIP receptor agonist currently in Phase 3 clinical development in China) became effective. In-licensing a late-stage GLP-1/GIP agonist enables us to study combinations with our products and product candidates in order to address muscle loss and potentially other comorbidities of obesity, such as cardiovascular diseases, diabetes, and liver conditions. Under the terms of the agreement, we made an $80.0 million up-front payment in July 2025. In addition, we are obligated to make additional payments upon achievement of development, regulatory, and sales milestones, as well as a low double-digit royalty on sales.

Tessera

In January 2026, our collaboration agreement with Tessera Therapeutics, Inc. to develop and commercialize TSRA-196 (Tessera's investigational program for the treatment of alpha-1 antitrypsin deficiency ("AATD")) became effective. Tessera will lead the initial first-in-human trial, while we will lead subsequent global development and commercialization. The parties will share worldwide development expenses and, if commercialized, any future profits or losses equally. Under the terms of the agreement, the Company made aggregate payments of $150.0 million in January 2026, consisting of an up-front payment and the purchase of Tessera preferred stock. In addition, we are obligated to make additional payments upon achievement of certain development milestones.

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Manufacturing

We currently manufacture bulk drug materials and products at our manufacturing facilities in Rensselaer, New York and Limerick, Ireland. These facilities consist of owned and leased manufacturing, office, laboratory, and warehouse space. In addition, we have constructed a fill/finish facility in Rensselaer, New York that is undergoing process validation and has yet to be approved for commercial production.

We currently have approximately 100,000 liters of cell culture capacity at our Rensselaer facility and approximately 120,000 liters of cell culture capacity at our Limerick facility. Each of these facilities is approved by the FDA and certain other regulatory agencies to manufacture our bulk drug materials and products.

Certain bulk drug materials and products are also manufactured by our collaborators, and certain raw materials or products necessary for the manufacture and formulation of our products and product candidates are provided by single-source unaffiliated third-party suppliers. In addition, we rely on our collaborators or third parties to perform packaging, filling, finishing, labeling, distribution, laboratory testing, and other services related to the manufacture of our products and product candidates. See Part I, Item 1A. "Risk Factors - Risks Related to Manufacturing and Supply" for further information.

Among the conditions for marketing approval of a new drug or biologic product is the requirement that the prospective manufacturer's quality control and manufacturing procedures conform to the good manufacturing practice ("GMP") regulations of the health authority. In complying with standards set forth in these regulations, manufacturers must continue to expend time, money, and effort in the areas of production and quality control to ensure full technical compliance. Manufacturing establishments, both foreign and domestic, are also subject to inspections by or under the authority of the FDA and by other national, federal, state, and local agencies.

Commercial

We commercialize our products both in the United States and other countries through our commercial group, which includes experienced professionals in the fields of marketing, sales, professional education, patient education, reimbursement and market access, trade and distribution, commercial operations, commercial analytics, and market research. In addition, we also co-commercialize certain products sold by our collaborators in the United States and other countries.

We sell our marketed products primarily to wholesalers, specialty distributors, pharmacies, hospitals, government agencies, physicians, and other healthcare providers. We promote approved medicines to healthcare professionals via our team of field employees, as well as medical journals, medical exhibitions, distribution of literature and samples, and online channels. In addition, we advertise certain products directly to consumers and maintain websites with information about our medicines. The commercial group also evaluates opportunities for our targets and product candidates and prepares for market launches of new medicines.

For the year ended December 31, 2025, we had sales to two customers that each accounted for more than 10% of total gross product revenue. On a combined basis, our product sales to these customers accounted for 77% of our total gross product revenue for the year ended December 31, 2025.

Competition

We face substantial competition from pharmaceutical and biotechnology companies. Our ability to compete depends, to a great extent, on how fast we can develop safe and effective product candidates, complete clinical testing and approval processes, and supply commercial quantities of the product to the market. Competition among products approved for sale is based on efficacy, safety, reliability, ease of administration, dosing frequency, availability, price, patent and other intellectual property position, and other factors.

Marketed Products

The table below provides an overview of the current competitive landscape for key products marketed by us and/or our collaborators in such products' currently approved indications. The table below is provided for illustrative purposes only and is not exhaustive. For additional information regarding the substantial competition these marketed products face, including potential future competition from product candidates in clinical development, see also Part I, Item 1A. "Risk Factors - Risks Related to Commercialization of Our Marketed Products, Product Candidates, and New Indications for Our Marketed Products - The commercial success of our products and product candidates is subject to significant competition."

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Marketed Product Competitor Product Competitor Indication Territory(a)

EYLEA HD and EYLEA(b)

Branded Competitor Products

LytenavaTM (bevacizumab gamma) Outlook Therapeutics, Inc. wAMD EU

Beovu® (brolucizumab) Injection Novartis AG wAMD, DME United States, EU, Japan

Biosimilar Competitor Products

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Fasenra® (benralizumab) AstraZeneca Asthma United States, EU, Japan

Exdensur® (depemokimab) GSK Asthma, CRSwNP United States, Japan

Rhapsido® Novartis AG CSU United States

Tecentriq® (atezolizumab) Roche Various cancers United States, EU, Japan

Imfinzi® (durvalumab) AstraZeneca Various cancers United States, EU, Japan

Bavencio® (avelumab) Pfizer/Merck KGaA Various cancers United States, EU, Japan

Jemperli® (dostarlimab) GSK Various cancers United States, EU

UnloxcytTM (cosibelimab) Checkpoint Therapeutics, Inc. CSCC United States

Product Candidates

Our late-stage and earlier-stage clinical candidates (including those being developed pursuant to agreements with our collaborators) face competition from many pharmaceutical and biotechnology companies. For example, we are aware of other pharmaceutical and biotechnology companies actively engaged in the research and development of antibody-based products (including bispecific antibodies, multispecific antibodies, and/or antibody-drug conjugates) and gene therapy-based products against targets that are also the targets of our early- and late-stage product candidates. These companies are using various technologies in competition with our VelocImmune technology and our other antibody generation technologies, including their own antibody generation technologies and other approaches such as RNAi, chimeric antigen receptor T ("CAR-T") cell, and gene therapy technologies. We are also aware of other companies developing or marketing small molecules that may compete with our antibody product candidates in various indications, if such product candidates obtain regulatory approval in those indications.

For additional information regarding our product candidates (including those being developed in collaboration with our collaborators) and the substantial competition they face, see also Part I, Item 1A. "Risk Factors - Risks Related to Commercialization of Our Marketed Products, Product Candidates, and New Indications for Our Marketed Products - The commercial success of our products and product candidates is subject to significant competition."

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Other Areas

Many pharmaceutical and biotechnology companies are attempting to discover new therapeutics for indications in which we invest substantial time and resources. In these and related areas, intellectual property rights have been sought and certain rights have been granted to competitors and potential competitors of ours, and we may be at a substantial competitive disadvantage in such areas as a result of, among other things, our inferior intellectual property position or lack of experience, trained personnel, and expertise. A number of corporate and academic competitors are involved in the discovery and development of novel therapeutics that are the focus of other research or development programs we are now conducting. Some of these competitors are currently conducting advanced preclinical and clinical research programs in these areas. These and other competitors also may have established substantial intellectual property and other competitive advantages.

If any of these or other competitors announces a successful clinical study involving a product that may be competitive with one of our product candidates or the grant of marketing approval by a regulatory agency for a competitive product, such developments may have an adverse effect on our business, operating results, financial condition, cash flows, or future prospects.

We also compete with academic institutions, governmental agencies, and other public or private research organizations, which conduct research, seek patent and other intellectual property protection, and establish collaborative arrangements for the development and marketing of products that would provide royalties or other consideration for use of their technology. These institutions have become more active in seeking patent and other intellectual property protection and licensing arrangements to collect royalties or other consideration for use of the technology they have developed. Products developed in this manner may compete directly with products we develop. We also compete with others in acquiring technology from these institutions, agencies, and organizations.

Patents, Trademarks, and Trade Secrets

We rely on a combination of intellectual property laws, including patent, trademark, copyright, trade secret, and domain name protection laws, as well as confidentiality and license agreements, to protect our intellectual property and proprietary rights.

Our success depends, in part, on our ability to obtain patents, maintain trade secret protection, and operate without infringing on the proprietary rights of third parties (see Part I, Item 1A. "Risk Factors - Risks Related to Intellectual Property and Market Exclusivity - We may be restricted in our development, manufacturing, and/or commercialization activities by patents or other proprietary rights of others, and could be subject to awards of damages if we are found to have infringed such patents or rights"; and Note 16 to our Consolidated Financial Statements). Our policy is to file patent applications to protect technology, inventions, and improvements that we consider important to our business and operations. We hold an ownership interest in a number of issued patents in the United States and other countries with respect to our products and technologies. In addition, we hold an ownership interest in thousands of patent applications in the United States and other countries.

Our patent portfolio includes granted patents and pending patent applications covering our VelociSuite technologies, including our VelocImmune mouse platform (used to generate fully human antibodies). Patent protection for certain of our VelociSuite technologies extends to 2042 based on remaining issued patents, and we continue to file new patent applications directed to improvements to these technology platforms.

Our patent portfolio also includes issued patents and pending applications relating to commercialized products and our product candidates in clinical development. These patents cover, among other things, proteins, DNA and RNA molecules, manufacturing patents, method of use patents, and pharmaceutical compositions and formulations.

The following table describes our U.S. patents, European patents ("EP"), and Japanese patents ("JP") that are of particular relevance to key products marketed or otherwise commercialized by us and/or our collaborators. The noted expiration dates include any patent term adjustments, and certain of these patents may also be entitled to term extensions. We continue to pursue additional patents and patent term extensions in the United States and other jurisdictions covering various aspects of our products that may, if issued, extend exclusivity beyond the expiration of the patents listed in the table below. One or more patents with the same or earlier expiry date may fall under the same "general subject matter class" for certain products and may not be separately listed. We also own various patents with claims relating to methods of making, formulating, and/or using the active molecules contained within our key products, but that do not cover indications, methods of use or processes currently approved by regulatory agencies or used by us and/or our collaborators. Such patents are not listed in the following table.

Product Molecule Territory Patent No. General Subject Matter Class Expiration

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EYLEA HD (continued) US 10,828,345 Methods of Treatment January 11, 2032

EP 2944306 Formulation (Supplementary Protection Certificate) (May 25, 2028)(b)

Dupixent dupilumab US 7,608,693 Composition of Matter March 28, 2031(e)

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Dupixent (continued) EP 2356151 Composition of Matter October 27, 2029(b)

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Dupixent (continued) JP 7,609,901 Methods of Treatment August 20, 2033

Libtayo cemiplimab US 9,987,500 Composition of Matter September 18, 2035

In addition to our patent portfolio, in the United States and certain other countries, our competitive position may be enhanced due to the availability of market exclusivity under relevant law (for additional information regarding market exclusivity, see Part I, Item 1A. "Risk Factors - Risks Related to Intellectual Property and Market Exclusivity - Loss or limitation of patent rights, and regulatory pathways for biosimilar competition, have in the past reduced and could reduce in the future the duration of market exclusivity for our products"). The effect of expiration of a patent relating to a particular product also depends upon other factors, such as the nature of the market and the position of the product in it, the growth of the market, the complexities and economics of the process for manufacture of the active ingredient of the product, and the requirements of new drug provisions of the Federal Food, Drug, and Cosmetic Act or similar laws and regulations in other countries.

We also are the nonexclusive licensee of a number of additional patents and patent applications. These include a license agreement with Bristol-Myers Squibb, E. R. Squibb & Sons, L.L.C., and Ono Pharmaceutical Co., Ltd. to obtain a license under

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certain patents owned and/or exclusively licensed by one or more of these parties that includes the right to develop and sell Libtayo. Under the agreement, we paid royalties of 8.0% on worldwide sales of Libtayo through December 31, 2023, and are obligated to pay royalties of 2.5% from January 1, 2024 through December 31, 2026.

Patent law relating to the patentability and scope of claims in the biotechnology field is evolving and our patent rights are subject to this additional uncertainty. The degree of patent protection that will be afforded to our products in the United States and other important commercial markets is uncertain and is dependent upon the scope of protection decided upon by the patent offices, courts, and governments in these countries. There is no certainty that our existing patents or others, if obtained, will provide us protection from competition or provide commercial benefit.

Others may independently develop similar products or processes to those developed by us, duplicate any of our products or processes or, if patents are issued to us, design around any products and processes covered by our patents. We expect to continue, when appropriate, to file product and process applications with respect to our inventions. However, we may not file any such applications or, if filed, the patents may not be issued. Patents issued to or licensed by us may be infringed by the products or processes of others.

We seek to file and maintain trademarks around the world based on commercial activities in most jurisdictions where we have, or desire to have, a business presence for a particular product or service. Trademark protection varies in accordance with local law, and continues in some countries as long as the trademark is used and in other countries as long as the trademark is registered. Trademark registrations generally are for fixed but renewable terms.

Defense and enforcement of our intellectual property rights is expensive and time consuming, even if the outcome is favorable to us. It is possible that patents issued or licensed to us will be successfully challenged, that a court may find that we are infringing validly issued patents of third parties, or that we may have to alter or discontinue the development of our products or pay licensing fees to take into account patent rights of third parties (see Part I, Item 1A. "Risk Factors - Risks Related to Intellectual Property and Market Exclusivity - We may be restricted in our development, manufacturing, and/or commercialization activities by patents or other proprietary rights of others, and could be subject to awards of damages if we are found to have infringed such patents or rights"; and Note 16 to our Consolidated Financial Statements).

Government Regulation

Regulation by government authorities in the United States and other countries is a significant factor in the research, development, manufacture, and marketing of our products and our product candidates. A summary of the primary areas of government regulation that are relevant to our business is provided below. For a description of material regulatory risks we face, also refer to Part I, Item 1A. "Risk Factors."

Preclinical Requirements

The activities required before a product candidate may be marketed in the United States or elsewhere begin with preclinical tests. Preclinical tests include laboratory evaluations of, among other things, product chemistry and formulation and toxicological and pharmacological studies in animal species to assess the toxicity and dosing of the product candidate. In the United States, certain preclinical trials must comply with the FDA's Good Laboratory Practice requirements ("GLPs") and the U.S. Department of Agriculture's Animal Welfare Act. The results of these studies must be submitted to the FDA or the relevant regulatory authority outside the United States as part of an IND or other clinical trial application (as applicable), which must be reviewed by the FDA or the relevant government authority before proposed clinical testing can begin in the applicable country or jurisdiction. In the United States, unless the FDA raises concerns, the IND becomes effective 30 days following its receipt by the FDA, and the clinical trial proposed in the IND may begin. The FDA or other regulatory authorities may ask for additional data in order to begin a clinical trial. Rules that are equivalent in scope but which vary in application apply in other countries.

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Product Approval

All of our product candidates require regulatory approval by relevant government authorities before they can be commercialized. In particular, human therapeutic products are subject to rigorous preclinical and clinical trials and other pre-market approval requirements by the FDA, European Medicines Agency ("EMA"), and regulatory authorities of other jurisdictions. The structure and substance of the FDA and other countries' pharmaceutical regulatory practices may evolve over time. The ultimate outcome and impact of such developments cannot be predicted.

Clinical trials involve the administration of a drug or biologic to healthy human volunteers or to patients under the supervision of a qualified investigator. The conduct of clinical trials is subject to extensive regulation, including compliance with the FDA's bioresearch monitoring regulations and Good Clinical Practice requirements ("GCPs"), which establish standards for recruiting for, conducting, recording data from, and reporting the results of, clinical trials, and are intended to assure that the data and reported results are credible, representative, and accurate, and that the rights, safety, and well-being of study participants are protected. Clinical trials must be conducted under protocols that detail the study objectives, parameters for monitoring safety, and the efficacy criteria, if any, to be evaluated. In addition, each clinical trial must be reviewed and approved by, and conducted under the auspices of, an Institutional Review Board ("IRB") for each clinical site within the United States or, where applicable, an Ethics Committee and/or the competent authority for clinical sites outside the United States. Companies sponsoring the clinical trials, investigators, and IRBs/Ethics Committees also must comply with, as applicable, regulations and guidelines for obtaining informed consent from the study patients, following the protocol and investigational plan, adequately monitoring the clinical trial, and timely reporting of adverse events. Foreign studies conducted under an IND must meet the same requirements that apply to studies being conducted in the United States. Data from a foreign study not conducted under an IND generally may be submitted in support of an application for marketing approval if the study was conducted in accordance with GCPs and the FDA is able to validate the data. The sponsor of a clinical trial or the sponsor's designated responsible party may be required to register certain information about the trial and disclose certain results on government or independent registry websites, such as clinicaltrials.gov.

Typically, clinical testing involves a three-phase process, which may overlap or be subdivided in some cases. Phase 1 trials are usually conducted with a small number of healthy volunteers to determine the early safety profile, metabolism, and pharmacological actions of the product candidate, the side effects associated with increasing doses, and, if possible, to gain early evidence of effectiveness. Although Phase 1 trials are typically conducted in healthy human subjects, in some instances, the trial subjects are patients with the targeted disease or condition. Phase 2 clinical trials are conducted with a relatively small sample of the intended patient population to provide enough data to evaluate the preliminary safety, tolerability, and efficacy of different potential doses of the product candidate. Phase 3 clinical trials are larger trials conducted with patients with the target disease or disorder intended to gather additional information about dosage, safety, and effectiveness necessary to evaluate the drug's or biologic's overall risk-benefit profile. Phase 3 data often form the core basis on which the FDA and comparable foreign regulatory authorities evaluate a product candidate's safety and effectiveness when considering the product application for regulatory approval. If concerns arise about the safety of the product candidate, the FDA or other regulatory authorities can stop clinical trials by placing them on a "clinical hold" pending receipt of additional data, which can result in a delay or termination of a clinical development program. The sponsoring company, the FDA or other regulatory authorities, or the IRB or Ethics Committee and competent authority may suspend or terminate a clinical trial at any time on various grounds, including a finding that the patients are being exposed to an unacceptable health risk.

The results of the preclinical and clinical testing of a drug or biologic product candidate are then submitted to the FDA in the form of an NDA for a drug or a BLA for a biologic for evaluation to determine whether the product candidate may be approved for commercial sale under the Federal Food, Drug, and Cosmetic Act or Public Health Service Act. When an NDA or BLA is submitted, the FDA makes an initial determination as to whether the application is sufficiently complete to be accepted for review. If the application is not, the FDA may refuse to accept the application for filing and request additional information. A refusal to file, which requires resubmission of the NDA or BLA with the requested additional information, delays review of the application. If the application is accepted for review, the FDA reviews the application to determine, among other things, whether a product is safe and effective for its intended use and whether the manufacturing controls are adequate to assure and preserve the product's identity, strength, quality, and purity.

FDA performance goals generally provide for action on an NDA or BLA within 10 months of the 60-day filing date (or within 12 months of the application submission). That deadline can be extended by FDA under certain circumstances, including by the FDA's requests for additional information. The targeted action date can be 6 months after the 60-day filing date (or 8 months after application submission) for product candidates that are granted priority review designation because they are intended to treat serious or life-threatening conditions and demonstrate the potential to address unmet medical needs. The FDA has other programs to expedite development and review of product candidates that address serious or life-threatening conditions.

For some applications, the FDA may convene an advisory committee to seek insights and recommendations on issues relevant to approval of the application. Although the FDA is not bound by the recommendation of an advisory committee, the agency

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considers such recommendations carefully when making decisions. Before approving a new drug or biologic product, the FDA also requires that the facilities at which the product will be manufactured or advanced through the supply chain be in compliance with current Good Manufacturing Practices, or cGMP, requirements and regulations governing, among other things, the manufacture, shipment, and storage of the product. The FDA will typically inspect such facilities for compliance with these requirements and regulations prior to approving a marketing application. The FDA also can audit the sponsor of the NDA or BLA to determine if the clinical studies were conducted in compliance with current GCPs. After review of an NDA or BLA, the FDA may grant marketing approval, request additional information, or issue a CRL outlining the deficiencies in the submission. The CRL may require additional testing or information, including additional preclinical or clinical data, for the FDA to reconsider the application. Even if such additional information and data are submitted, the FDA may decide that the application still does not meet the standards for approval. Data from clinical trials are not always conclusive and the FDA may interpret data differently than the sponsor. If FDA grants approval, an approval letter authorizes commercial marketing of the product candidate with specific prescribing information for specific indications.

Any approval required by the FDA for any of our product candidates may not be obtained on a timely basis, or at all. The designation of a clinical trial as being of a particular phase is not necessarily indicative that such a trial will be sufficient to satisfy the parameters of a particular phase, and a clinical trial may contain elements of more than one phase notwithstanding the designation of the trial as being of a particular phase. The results of preclinical studies or early-stage clinical trials may not predict long-term safety or efficacy of our compounds when they are tested or used more broadly in humans. Additionally, as a condition of approval, the FDA may impose restrictions that could affect the commercial prospects of a product and increase our costs, such as a Risk Evaluation and Mitigation Strategy ("REMS") to mitigate certain specific safety risks, and/or post-approval commitments or requirements to conduct additional clinical trials or non-clinical studies or to conduct surveillance programs to monitor the product's effects.

Approval of a product candidate by comparable regulatory authorities in jurisdictions outside the United States is generally required prior to commencement of marketing of the product in those jurisdictions. The approval procedure varies among jurisdictions and may involve different or additional testing, and the time required to obtain such approval may differ from that required for FDA approval. Approval by a regulatory authority in one jurisdiction does not guarantee approval by comparable regulatory authorities in other jurisdictions. In the European Economic Area ("EEA") (which is comprised of 27 Member States of the EU plus Norway, Iceland, and Liechtenstein), medicinal products can only be commercialized after a related Marketing Authorization has been granted. Marketing authorization for certain drugs and biologics (including medicinal products that are derived from biotechnology processes) that contain a new active substance indicated for the treatment of certain diseases (such as cancer, diabetes, neurodegenerative diseases, or autoimmune and other immune dysfunctions) or that are designated orphan medicines must be obtained through a centralized procedure, which allows a company to submit a single application to the EMA. If a related positive opinion is provided by the EMA, the EC will grant a centralized marketing authorization that is valid in the EEA.

In many jurisdictions, pediatric data or an approved Pediatric Investigation Plan ("PIP"), or a waiver of such studies, is required to have been approved by regulatory authorities prior to submission of a marketing application. In some EU countries, we may also be required to have an approved PIP before we can begin enrolling pediatric patients in a clinical trial. In the United States, under the Pediatric Research Equity Act ("PREA"), certain applications for approval must include an assessment, generally based on clinical study data, of the safety and effectiveness of the subject product in relevant pediatric populations, unless a waiver or deferral is granted. However, a pediatric study plan is not required for orphan products and the timing of the submission is subject to negotiation with FDA, but such plan cannot be submitted later than submission of an application for marketing approval.

Various federal, state, and foreign statutes and regulations also govern or influence the research, manufacture, safety, labeling, storage, record keeping, marketing, transport, and other aspects of developing and commercializing pharmaceutical product candidates. The lengthy process of seeking these approvals and the compliance with applicable statutes and regulations require the expenditure of substantial resources. Any failure by us or our collaborators or licensees to obtain, or any delay in obtaining, regulatory approvals could adversely affect the manufacturing or marketing of our products and our ability to receive product or royalty revenue.

For additional information regarding U.S. and foreign regulatory approval processes and requirements, see Part I, Item 1A. "Risk Factors - Risks Related to Maintaining Approval of Our Marketed Products and the Development and Obtaining Approval of Our Product Candidates and New Indications for Our Marketed Products - Obtaining and maintaining regulatory approval for drug and biologic products is costly, time-consuming, and highly uncertain. If we or our collaborators do not maintain regulatory approval for our marketed products, or obtain regulatory approval for our product candidates, we will not be able to market or sell them; and if we do not obtain approvals for new indications for our marketed products, we may not be able to realize the full commercial potential of such products. Any of the foregoing may materially and negatively impact our business, prospects, operating results, and financial condition."

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Post-Approval Regulation

The FDA and comparable regulatory authorities in other jurisdictions may also require us to conduct additional clinical trials or to make certain changes related to a product after granting approval of the product. The FDA has the explicit authority to require postmarketing studies (also referred to as post-approval studies) and labeling changes based on new safety information and may impose and enforce a REMS at the time of approval or after the product is on the market. Post-approval modifications to the drug or biologic, such as changes in indications, labeling, or manufacturing processes or facilities, may require a sponsor to develop additional data or conduct additional preclinical studies or clinical trials, to be submitted in a new or supplemental NDA or BLA, which would require FDA approval.

Following approval, the FDA and comparable regulatory authorities outside the United States regulate the marketing and promotion of our products, which must comply with the Food, Drug, and Cosmetic Act and applicable FDA regulations and standards thereunder and equivalent foreign laws. The review of promotional activities by the FDA and comparable regulatory authorities outside the United States includes, but is not limited to, healthcare provider-directed and direct-to-consumer advertising, communications regarding unapproved uses, industry-sponsored scientific and educational activities, promotional activities involving the Internet, and sales representatives' communications. FDA and comparable foreign regulatory authorities' regulations impose restrictions on manufacturers' communications regarding unapproved uses, but under certain conditions manufacturers may engage in non-promotional, balanced, scientific communication regarding such use. Failure to comply with applicable FDA and comparable foreign regulatory authorities' requirements and restrictions in this area may subject a company to adverse publicity and enforcement action by the FDA, the Department of Justice, or the Office of the Inspector General of the Department of Health and Human Services, as well as state authorities and comparable regulatory authorities outside the United States. This could subject a company to a range of penalties that could have a significant commercial impact, including civil and criminal fines and agreements that materially restrict the manner in which a company promotes or distributes a drug or biologic. See Part I, Item 1A. "Risk Factors - Other Regulatory and Litigation Risks - Our business activities have been, and may in the future be, challenged under U.S. federal or state and foreign healthcare laws, which may subject us to civil or criminal proceedings, investigations, or penalties."

Adverse-event reporting and submission of periodic reports are required following marketing approval. The FDA requires NDA and BLA holders to employ a system for obtaining and reviewing safety information, adverse events, and product complaints associated with each drug or biologic and to submit safety reports to the FDA, with expedited reporting timelines in certain situations. Based on new safety information after approval, the FDA can, among other things, mandate product labeling changes, require new post-marketing studies, impose or modify a REMS for the product, or suspend or withdraw approval of the product. We may be subject to audits by the FDA and other regulatory authorities to determine whether we are complying with the applicable requirements. Rules that are equivalent in scope but which vary in application apply in jurisdictions outside the United States in which we sell products.

The holder of an EU marketing authorization for a medicinal product must also comply with the EU's pharmacovigilance legislation. This includes requirements to conduct pharmacovigilance, or the assessment and monitoring of the safety of medicinal products. Marketing authorization holders are required to maintain a Pharmacovigilance System Master File ("PSMF"), which seeks to support and document compliance of the marketing authorization holder with the requirements of EU pharmacovigilance legislation. Marketing authorization holders are also required to have a Qualified Person for Pharmacovigilance ("QPPV"), who, among other things, maintains the PSMF. A QPPV must reside in the EEA and must also prepare pharmacovigilance reports, respond to potential requests from competent authorities concerning pharmacovigilance on a 24-hour basis, and provide competent authorities with any other information that may be relevant to the safety of the medicinal product in accordance with Good Pharmacovigilance Practices.

The EC can also require marketing authorization holders to conduct post-authorization safety and/or efficacy studies. A post-authorization safety study ("PASS") is a study that is carried out after a medicinal product has been authorized for marketing to obtain further information on a medicinal product's safety, or to measure the effectiveness of risk-management measures. Such studies may be clinical trials or non-interventional studies. A post-authorization efficacy study ("PAES") is a study that is carried out for complementing available efficacy data in the light of well-reasoned scientific uncertainties on aspects of the evidence of benefits that are to be or only can be addressed post-authorization. The EC may, in particular, impose a PASS and/or PAES on a marketing authorization holder when a marketing authorization is granted subject to conditions. The EC may grant a conditional marketing authorization in the interest of public health, when there is less comprehensive clinical data available than typically would be required, if the EC considers that the benefit of immediate availability may outweigh the risk that the absence of the required clinical data poses.

In addition, we and our third-party suppliers are required to maintain compliance with cGMP, and are subject to inspections by the FDA or comparable regulatory authorities in other jurisdictions to seek to confirm such compliance. Changes of suppliers or modifications in methods of manufacturing may require amending our application(s) to the FDA or such comparable foreign

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regulatory authorities and acceptance of the change by the FDA or such comparable foreign regulatory authorities prior to release of product(s). FDA regulations also require investigation and correction of any deviations from cGMP and impose reporting and documentation requirements upon us and our third-party suppliers. Prescription drug manufacturers in the U.S. must comply with applicable provisions of the Drug Supply Chain Security Act and provide and receive product tracing information, maintain appropriate licenses, ensure they only work with other properly licensed entities, and have procedures in place to identify and properly handle suspect and illegitimate products. We may also be subject to state regulations related to the manufacturing and distribution of our products.

Failure to comply with these laws, regulations, and conditions of product approval may lead the FDA and comparable regulatory authorities in other jurisdictions to take regulatory action or seek sanctions, including fines, issuance of warning letters, civil penalties, injunctions, suspension of manufacturing operations, operating restrictions, withdrawal of FDA approval of a product, seizure or recall of products, and criminal prosecution.

Pricing and Reimbursement

Sales in the United States of our marketed products are dependent, in large part, on the availability and extent of reimbursement from third-party payors, including private payor healthcare and insurance programs, health maintenance organizations, pharmacy benefit management companies, and government programs such as Medicare and Medicaid. Sales of our marketed products in other countries are dependent, in large part, on coverage and reimbursement mechanisms and programs administered by health authorities in those countries. See Part I, Item 1A. "Risk Factors - Risks Related to Commercialization of Our Marketed Products, Product Candidates, and New Indications for Our Marketed Products - Product reimbursement and coverage policies and practices, pricing regulations and requirements, and our pricing strategy could change due to various factors beyond our control, which may adversely impact our business, prospects, operating results, and financial condition."

We participate in, and have certain price reporting obligations to, the Medicaid Drug Rebate program, state Medicaid supplemental rebate program(s), and other governmental pricing programs. We also have obligations to report the average sales price for certain drugs to the Medicare program. Under the Medicaid Drug Rebate program, we are required to pay a rebate to each state Medicaid program for our covered outpatient drugs that are dispensed to Medicaid beneficiaries and paid for by a state Medicaid program as a condition of having federal funds being made available for our drugs under Medicaid and Part B of the Medicare program.

Medicaid is a joint federal and state program that is administered by the states for low-income and disabled beneficiaries. Medicaid rebates are based on pricing data reported by us on a monthly and quarterly basis to the Centers for Medicare & Medicaid Services ("CMS"), the federal agency that administers the Medicaid and Medicare programs. These data include the average manufacturer price and, in the case of innovator products, the best price for each drug which, in general, represents the lowest price available from the manufacturer to any entity in the U.S. in any pricing structure, calculated to include all sales and associated rebates, discounts, and other price concessions. The amount of the rebate is adjusted upward if the average manufacturer price increases more than inflation (measured by reference to the Consumer Price Index - Urban).

If we become aware that our Medicaid reporting for a prior quarter was incorrect, or has changed as a result of recalculation of the pricing data, we are obligated to resubmit the corrected data for up to three years after those data originally were due, which revisions could affect our rebate liability for prior quarters. If we fail to pay the required rebate amount or report pricing data on a timely basis, we may be subject to civil monetary penalties and/or termination of our Medicaid Drug Rebate program agreement, in which case federal payments may not be available under Medicaid or Medicare Part B for our covered outpatient drugs. For additional information regarding risks related to our price reporting and rebate payment obligations, see Part I, Item 1A. "Risk Factors - Other Regulatory and Litigation Risks - If we fail to comply with our reporting and payment obligations under the Medicaid Drug Rebate program or other governmental pricing programs, we could be subject to additional reimbursement requirements, penalties, sanctions, and fines, which could have a material adverse effect on our business, financial condition, results of operations, and future prospects."

Medicare is a federal program that is administered by the federal government that covers individuals age 65 and over or that are disabled as well as those with certain health conditions. Medicare Part B generally covers drugs that must be administered by physicians or other healthcare practitioners; are provided in connection with certain durable medical equipment; or are certain oral anti-cancer drugs and certain oral immunosuppressive drugs. Medicare Part B pays for such drugs under a payment methodology based on the average sales price of the drugs. Manufacturers, including us, are required to report average sales price information to CMS on a quarterly basis. The manufacturer-submitted information may be used by CMS to calculate Medicare payment rates. Manufacturers must pay refunds to Medicare for single-source drugs or biological products, or biosimilar biological products, reimbursed under Medicare Part B and packaged in single-dose containers or single-use packages for units of discarded drug reimbursed by Medicare Part B in excess of 10% of total allowed charges under Medicare Part B for that drug. Manufacturers that fail to pay refunds could be subject to civil monetary penalties. Further, the Inflation Reduction Act ("IRA") has established a Medicare Part B inflation rebate scheme under which, generally speaking, manufacturers owe rebates if the average sales price of

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a Part B drug increases faster than the pace of inflation. Failure to timely pay a Part B inflation rebate is subject to a civil monetary penalty.

The IRA also created a drug price negotiation program requiring the government to set prices for select high-expenditure drugs covered under Medicare Parts B and D. Starting in 2023 and 2026, the government is authorized to select Part D and Part B drugs, respectively, for inclusion in the drug price negotiation program, with established prices to go into effect for selected Part D drugs in 2026 and for selected Part B drugs in 2028, in each case absent certain disqualifying events. Failure to comply with requirements under the drug price negotiation program is subject to an excise tax and a civil monetary penalty. This or any other legislative change could impact the market conditions for our products. See Part I, Item 1A. "Risk Factors - Risks Related to Commercialization of Our Marketed Products, Product Candidates, and New Indications for Our Marketed Products - Product reimbursement and coverage policies and practices, pricing regulations and requirements, and our pricing strategy could change due to various factors beyond our control, which may adversely impact our business, prospects, operating results, and financial condition."

Civil monetary penalties can be applied if we are found to have knowingly submitted any false pricing or other information to the government, if we are found to have made a misrepresentation in the reporting of our average sales price, or if we fail to submit the required data on a timely basis. Such conduct also could be grounds for CMS to terminate our Medicaid drug rebate agreement, in which case federal payments may not be available under Medicaid or Medicare Part B for our covered outpatient drugs.

Federal law requires that any company that participates in the Medicaid Drug Rebate program also participate in the Public Health Service's 340B drug pricing program (the "340B program") in order for federal funds to be available for the manufacturer's drugs under Medicaid and Medicare Part B. The 340B program, which is administered by the Health Resources and Services Administration ("HRSA"), requires participating manufacturers to agree to charge statutorily defined covered entities no more than the 340B "ceiling price" for the manufacturer's covered outpatient drugs. Covered entities include hospitals that serve a disproportionate share of financially needy patients, community health clinics, and other entities that receive certain types of grants under the Public Health Service Act. The federal Patient Protection and Affordable Care Act (the "PPACA") expanded the list of covered entities to include certain free-standing cancer hospitals, critical access hospitals, rural referral centers, and sole community hospitals, but exempts "orphan drugs" from the ceiling price requirements for these covered entities. The 340B ceiling price is calculated using a statutory formula, which is based on the average manufacturer price and Medicaid rebate amount for the covered outpatient drug as calculated under the Medicaid Drug Rebate program. In general, products subject to Medicaid price reporting and rebate liability are also subject to the 340B ceiling price calculation and discount requirement.

HRSA issued a final regulation regarding the calculation of the 340B ceiling price and the imposition of civil monetary penalties on manufacturers that knowingly and intentionally overcharge covered entities. If we are found to have knowingly and intentionally charged 340B covered entities more than the statutorily mandated ceiling price, we could be subject to significant civil monetary penalties and/or such failure also could be grounds for HRSA to terminate our agreement to participate in the 340B program, in which case our covered outpatient drugs would no longer be eligible for federal payment under Medicaid or Medicare Part B. Moreover, HRSA has established an administrative dispute resolution ("ADR") process for claims by covered entities that a manufacturer has engaged in overcharging, and by manufacturers that a covered entity violated the prohibitions against diversion or duplicate discounts. Such claims are to be resolved through an ADR panel of government officials rendering a decision that could be appealed only in federal court. An ADR proceeding could subject us to onerous procedural requirements and could result in additional liability. HRSA has also implemented a price reporting system under which we are required to report our 340B ceiling prices to HRSA on a quarterly basis, which then publishes those prices to 340B covered entities.

In order to be eligible to have our products paid for with federal funds under the Medicaid and Medicare Part B programs and purchased by certain federal agencies and grantees, we participate in the U.S. Department of Veterans Affairs ("VA") Federal Supply Schedule ("FSS") pricing program. FSS participation is required for our products to be purchased by the VA, Department of Defense ("DoD"), Coast Guard, and Public Health Service ("PHS"). Prices for innovator drugs purchased by the VA, DoD, Coast Guard, and PHS are subject to a cap (known as the "Federal Ceiling Price") equal to 76% of the annual non-federal average manufacturer price ("non-FAMP") minus, if applicable, an additional discount. The additional discount applies if non-FAMP increases more than inflation (measured by reference to the Consumer Price Index - Urban). We also participate in the Tricare Retail Pharmacy Program, under which we pay quarterly rebates to DoD for prescriptions of our innovator drugs dispensed to Tricare beneficiaries through Tricare Retail network pharmacies. The governing statute provides for civil monetary penalties for failure to provide information timely or for knowing submission of false information to the government.

Medicare Part D provides coverage to enrolled Medicare patients for self-administered drugs (i.e., drugs that are not administered by a physician). Medicare Part D is administered by private prescription drug plans approved by the U.S. government and, subject to detailed program rules and government oversight, each drug plan establishes its own Medicare Part D formulary for prescription drug coverage and pricing, which the drug plan may modify from time to time. The prescription drug plans negotiate

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pricing with manufacturers and pharmacies, and may condition formulary placement on the availability of manufacturer discounts. In addition, effective January 1, 2025, the IRA replaced the coverage gap discount program with a new manufacturer discount program under which manufacturers, including us, are required to provide to CMS a 10% discount on covered Part D drugs utilized by Medicare Part D beneficiaries when those beneficiaries are in the initial phase of the Part D benefit design (i.e., the phase during which the beneficiary must pay a copayment or coinsurance amount) and a 20% discount when those beneficiaries are in the catastrophic phase of Part D coverage (i.e., the phase after the beneficiary incurs costs above the initial phase's annual out-of-pocket limit). In addition, the IRA has established a Medicare Part D inflation rebate scheme under which, generally speaking, manufacturers will owe additional rebates if the average manufacturer price of a Part D drug increases faster than the pace of inflation. Failure to timely pay a Part D manufacturer discount program amount or inflation rebate or otherwise comply with obligations under the Medicare Part D inflation rebate scheme is subject to a civil monetary penalty.

Private payor healthcare and insurance providers, health maintenance organizations, and pharmacy benefit managers in the United States are adopting more aggressive utilization management techniques and are increasingly requiring significant discounts and rebates from manufacturers as a condition to including products on formulary with favorable coverage and copayment/coinsurance. These payors may not cover or adequately reimburse for use of our products or may do so at levels that disadvantage them relative to competitive products.

Outside the United States, within the EU, our products are paid for by a variety of payors, with governments being the primary source of payment. Government health authorities in the EU determine or influence reimbursement of products, and set prices or otherwise regulate pricing. Negotiating prices with governmental authorities can delay commercialization of our products. Governments may use a variety of cost-containment measures to control the cost of products, including price cuts, mandatory rebates, value-based pricing, and reference pricing (i.e., referencing prices in other countries or prices of competitive products and using those reference prices to set a price). Budgetary pressures in many EU countries are continuing to cause governments to consider or implement various cost-containment measures, such as price freezes, increased price cuts and rebates, and expanded generic substitution and patient cost-sharing.

Other Regulatory Requirements

We are subject to healthcare "fraud and abuse" laws, such as the federal civil False Claims Act, the anti-kickback provisions of the federal Social Security Act, and other state and federal laws and regulations. Federal and state anti-kickback laws prohibit, among other things, payments or other remuneration to induce or reward someone to purchase, prescribe, endorse, or recommend a product that is reimbursed under federal or state healthcare programs. Federal false claims laws prohibit any person from knowingly presenting, or causing to be presented, a false claim for payment of government funds, or knowingly making, or causing to be made, a false statement to get a false claim paid. We are also subject to federal and state transparency laws that require manufacturers to report transfers of value made to certain healthcare professionals and healthcare organizations. We also have similar reporting obligations in other countries based on laws, regulations, and/or industry trade association requirements. See Part I, Item 1A. "Risk Factors - Other Regulatory and Litigation Risks - Our business activities have been, and may in the future be, challenged under U.S. federal or state and foreign healthcare laws, which may subject us to civil or criminal proceedings, investigations, or penalties."

We are subject to the Foreign Corrupt Practices Act, or FCPA, and similar anti-bribery or anti-corruption laws, regulations or rules of other countries in which we operate, including the U.K. Bribery Act. See Part I, Item 1A. "Risk Factors - Other Regulatory and Litigation Risks - Risks from the improper conduct of employees, agents, contractors, or collaborators could adversely affect our reputation and our business, prospects, operating results, and financial condition."

We are subject to privacy and data protection laws in the United States and abroad, including health privacy laws, data breach notification laws, consumer protection laws, data localization laws, biometric privacy laws, and genetic privacy laws.

In the United States, there are numerous federal and state laws and regulations governing data privacy of personal data and the collection, use, disclosure, and protection of health data, genetic data, consumer data, and children's data. At the federal level, most U.S. healthcare providers, including research institutions from which we or our collaborators obtain clinical trial data, are subject to privacy and security regulations promulgated under the Health Insurance Portability and Accountability Act of 1996, the Health Information Technology for Economic and Clinical Health Act, and their implementing regulations (collectively, "HIPAA"). While Regeneron is not directly subject to HIPAA, other than potentially with respect to providing certain employee benefits, we could be subject to criminal penalties if we, our affiliates, or our agents knowingly receive protected health information in a manner that is not permitted under HIPAA. The Federal Trade Commission ("FTC") also sets expectations for taking appropriate steps to safeguard consumers' personal information and for providing a level of privacy or security commensurate to promises made to individuals. Failure to meet these FTC standards may constitute unfair or deceptive acts or practices in violation of Section 5 of the FTC Act. The FTC also has the power to enforce the Health Breach Notification Rule, which imposes notification obligations on companies for breaches of certain health information contained in personal health records. Enforcement by the FTC under the FTC Act and Health Breach Notification Rule can result in civil penalties or

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enforcement actions. In addition, at the state level, many state consumer privacy laws recently went into effect and many other consumer privacy laws are expected to go into effect in the near future. These laws include certain transparency and other requirements to protect personal data and grant residents with certain rights regarding their personal data. These laws and regulations are constantly evolving and may impose limitations on our business activities.

Outside the United States, our activities subject us to additional data protection authority oversight and require us to comply with stringent local and regional data privacy laws. Such laws include the EU's General Data Protection Regulations ("GDPR"), which has a wide range of compliance obligations relating to the processing and protection of personal data. Violations of the GDPR carry significant financial penalties for noncompliance. The GDPR also confers a private right of action on data subjects and consumer associations to file complaints with data protection authorities, seek judicial remedies, and obtain compensation for damages resulting from violations of the GDPR. Many other jurisdictions outside the United States have adopted and continue to adopt varying privacy and data protection legislation, the continued emergence of which has increased the costs and complexity of compliance.

In addition to the foregoing, our present business is, and our future business may be, subject to regulation under the United States Atomic Energy Act, the Clean Air Act, the Clean Water Act, the Comprehensive Environmental Response, Compensation and Liability Act, the National Environmental Policy Act, the Toxic Substances Control Act, the Resource Conservation and Recovery Act, national restrictions, and other current and potential future local, state, federal, and foreign regulations.

Business Segments

We manage our business as one segment which includes all activities related to the discovery, development, and commercialization of medicines for serious diseases. For additional information related to our one segment, see our Consolidated Financial Statements and related notes.

Human Capital Resources

We compete in the highly competitive biotechnology and pharmaceuticals industries. Attracting, developing, and retaining skilled and experienced employees in research and development, manufacturing, sales and marketing, and other positions is crucial to our ability to compete effectively. Our ability to recruit and retain such employees depends on a number of factors, including our corporate culture, informed by our values and behaviors (which we call "The Regeneron Way") and our philosophy of "Doing Well by Doing Good"; talent development and career opportunities; and compensation and benefits.

Integrity is a core value at Regeneron. Both the Company and each of our employees have a responsibility to act ethically and with integrity at all times. Our Code of Business Conduct and Ethics brings together Regeneron's key policy principles and establishes the Company's expectations for all of our employees to act in accordance with applicable laws, rules, and regulations.

Workforce Profile

As of December 31, 2025, we had 15,410 full-time employees, consisting of 11,961 employed in the United States, 2,149 employed in Ireland, and 1,300 employed in other countries (primarily in the United Kingdom, Japan, and Germany). Of these employees, 2,591 were within our research and preclinical development organization, 2,274 were within our global clinical development and regulatory affairs organization, and 6,717 were within our industrial operations and product supply organization. Company-wide, over 1,800 of our full-time employees hold a Ph.D. and/or M.D. We also supplement our workforce with independent contractors, contingent workers, and temporary workers, as needed. Outside the United States, some of our employees are represented by works councils. Our management considers its relations with our employees to be good.

Culture and Development

Our employees represent a broad range of backgrounds, just like the people who take our medicines, and bring a wide array of perspectives and experiences that have helped us maintain our leadership position in the biotechnology and pharmaceuticals industries and the global marketplace. Our strategy is rooted in the understanding that a better workplace drives better science and that better science drives a better world. We believe that by fostering an inclusive culture and bringing different voices and perspectives to the discourse, we improve our ability to fulfill our mission to repeatedly bring important medicines to patients with serious diseases. Our employee-led cross-functional resource groups, open to all, help colleagues to connect around common interests and support our culture of inclusion and collaboration. In recent years, we have expanded our mentoring program and inclusive leadership workshops for senior leaders and new managers to increase leadership skills and connection among employees. In addition, in order to better understand our employees' perspectives, we measure inclusion and belonging as part of our annual employee engagement survey.

We invest significant resources to develop talent with the right capabilities to deliver the growth and innovation needed to support our continued success. Our Talent department is dedicated to promoting individual, leader, team, and organizational development

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through a number of tools and services. We offer a variety of professional development courses for our employees and support employee continuing education, including through educational reimbursement and tuition forgiveness programs. In addition, we continue to invest in our current and future leaders through a number of leadership development courses and programs and feedback and coaching opportunities. In 2025, approximately 25% of job openings were filled by existing employees who were seeking career development opportunities.

We continue to invest in the science, engineering, technology, and math ("STEM") talent pipeline with our most significant philanthropic investments in science education, a commitment we call STEM-FueledTM – our long-standing collection of programs and partnerships that fuel future scientific innovators to pursue bold ideas and advance world-changing solutions. This commitment includes our $100 million, 10-year commitment to support the Regeneron Science Talent Search ("STS"), the oldest and most prestigious high school science and mathematics competition in the United States, and $34 million, 5-year title sponsorship of the Regeneron International Science and Engineering Fair ("ISEF"), the world's largest global science competition for high school students.

Employee Engagement

We believe engaging our employees, from their first day and throughout their career, is key to fostering new ideas and driving commitment and productivity. We communicate frequently and transparently with our employees through a variety of communication methods, including video and written communications, company forums and town halls, annual engagement surveys, and pulse surveys.

Supporting our communities is at the heart of Regeneron's culture and we encourage community involvement to foster employee engagement. We are committed to fostering employee volunteerism and continue to deliver on our global responsibility goal to drive employee volunteer levels above national standards. Employees are encouraged and empowered to support organizations and causes that are important to them including through, among other things, our matching gift program, volunteer-time-off policy, and our annual company-wide service event, Day for Doing Good. In 2025, over 7,600 employees volunteered nearly 42,000 hours, including approximately 47% of our employees who volunteered nearly 28,700 hours to approximately 230 nonprofits during our Day for Doing Good. Additionally, through our Matching Gift Program, we matched approximately $2.4 million in employee contributions in 2025, supporting nearly 2,500 charities. In 2025, we were named to the Civic 50 of most community-minded companies in the United States for the ninth consecutive year.

The success of our employee engagement efforts is demonstrated by our employee retention rate of nearly 93% in 2025, as well as the fact that 81% of our employees who responded to our annual engagement survey said Regeneron is a great place to work. Additionally, we have placed in the top five for the past 15 years in Science magazine's annual "Top Employers Survey" of the global biotechnology and pharmaceutical industry.

Employee Wellness, Health, and Safety

The wellbeing of our employees is a primary focus as we believe that the most productive people are those who are at their best, both physically and mentally. We provide several programs related to employee health and wellness, including onsite amenities and programs such as meditation and prayer rooms and fitness centers. We also prioritize mental health initiatives and have taken further action to reduce or remove barriers to quality mental healthcare for our employees and their family members. In addition, we provide support for work-life balance through flex-time, remote working arrangements, child and elder care, and paid parental leave, among others.

Occupational health and safety is critical to our success. We are committed to meeting or exceeding all environmental, health, safety ("EHS") and security regulations and have a range of programs, policies, and procedures to ensure the safety of all people who come to work at Regeneron. In addition, our global responsibility goals included a commitment to focus on workplace injury prevention in our drive toward zero incidents.

Compensation and Benefits

We are committed to rewarding and supporting our employees in order to continue to attract and retain top talent. We believe this commitment supports our core strategy of creating and advancing a high-quality product pipeline and delivering medicines to people in need. Employee engagement, commitment, and achievements are key drivers of pipeline success and therefore our long-term performance. The primary underpinning of our pay philosophy is to award stock-based pay to all eligible employees to ensure that when we deliver for patients and for shareholders, everyone shares in the upside growth. Our practice, therefore, has been to award initial stock-based grants to all new hires, in addition to our comprehensive annual stock-based compensation program. Total employee compensation packages (which vary by country and region) include market-competitive pay (with the opportunity to receive above-market rewards), broad-based grants of stock-based awards, comprehensive healthcare benefits, parental leave, child and elder care support, retirement savings options, and matching contributions in connection with employee savings plans.

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Corporate Information

We make available free of charge on or through our Internet website (http://www.regeneron.com) our Annual Report on Form 10-K, Quarterly Reports on Form 10-Q, Current Reports on Form 8-K, and, if applicable, amendments to those reports filed or furnished pursuant to Section 13(a) or 15(d) of the Exchange Act, as soon as reasonably practicable after we electronically file such material with, or furnish it to, the Securities and Exchange Commission ("SEC").

Investors and other interested parties should note that we use our media and investor relations website (http://investor.regeneron.com) and our social media channels to publish important information about Regeneron, including information that may be deemed material to investors. We encourage investors and other interested parties to review the information we may publish through our media and investor relations website and the social media channels listed on our media and investor relations website, in addition to our SEC filings, press releases, conference calls, and webcasts.

The information contained on our websites and social media channels is not included as a part of, or incorporated by reference into, this report.

Item 1A. Risk Factors

We operate in an environment that involves a number of significant risks and uncertainties. We caution you to read the following risk factors, which have affected, and/or in the future could affect, our business, prospects, operating results, and financial condition. The risks described below include forward-looking statements, and actual events and our actual results may differ materially from these forward-looking statements. Additional risks and uncertainties not currently known to us or that we currently deem immaterial may also impair our business, prospects, operating results, and financial condition. Furthermore, additional risks and uncertainties are described under other captions in this report and should also be considered by our investors. For purposes of this section (as well as this report in general), references to our products encompass products marketed or otherwise commercialized by us and/or our collaborators or licensees; and references to our product candidates encompass product candidates in development by us and/or our collaborators or licensees (in the case of collaborated or licensed products or product candidates under the terms of the applicable collaboration or license agreements), unless otherwise stated or required by the context. In this section, we first provide a summary of the more significant risks and uncertainties we face and then provide a full set of risk factors and discuss them in greater detail.

Summary of Risk Factors

As noted above, we are subject to a number of risks that if realized could materially harm our business, prospects, operating results, and financial condition. Some of the more significant risks and uncertainties we face include those summarized below. The summary below is not exhaustive and is qualified by reference to the full set of risk factors set forth in this "Risk Factors" section. Please carefully consider all of the information in this Form 10-K, including the full set of risks set forth in this "Risk Factors" section, and in our other filings with the SEC before making an investment decision regarding Regeneron.

Commercialization Risks

•We are substantially dependent on the success of EYLEA HD, EYLEA, and Dupixent.

•Sales of our products are dependent on the availability and extent of coverage and reimbursement or copay assistance from third-party payors and other third parties, including private payors and government programs such as Medicare and Medicaid.

•Product reimbursement and coverage policies and practices, pricing regulations and requirements, and our pricing strategy could change due to various factors beyond our control, such as drug price control measures that have been or may be enacted or introduced in the United States by various federal and state authorities.

•The commercial success of our products is subject to significant competition from products or product candidates that may be superior to, or more established or cost effective than, our products or product candidates, including biosimilars.

•We and our collaborators on which we rely to commercialize some of our marketed products may be unable to continue to successfully commercialize or co-commercialize our products, both in and outside the United States.

Regulatory and Development Risks

•Drug development and obtaining and maintaining regulatory approval for drug and biologic products is costly, time-consuming, and highly uncertain.

•Serious complications or side effects in connection with the use or development of our products or product candidates could cause our regulatory approvals to be revoked or limited or lead to delay or discontinuation of development of our product candidates or new indications for our marketed products.

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•We may be unable to formulate or manufacture our product candidates in a way that is suitable for clinical or commercial use, which would delay or prevent continued development of such candidates and/or receipt of regulatory approval or commercial sale.

•Many of our products are intended to be used in combination with drug-delivery devices, which may result in additional regulatory, commercialization, and other risks.

Intellectual Property and Market Exclusivity Risks

•We may not be able to protect the confidentiality of our trade secrets, and our patents or other means of defending our intellectual property may be insufficient to protect our proprietary rights.

•Patents or proprietary rights of others may restrict our development, manufacturing, and/or commercialization efforts and subject us to patent litigation and other proceedings that could find us liable for damages.

•Loss or limitation of patent rights, and regulatory pathways for biosimilar competition, have in the past reduced and could reduce in the future the duration of market exclusivity for our products.

Manufacturing and Supply Risks

•We rely on limited internal and contracted manufacturing and supply chain capacity, which could adversely affect our ability to commercialize our products and to advance our clinical pipeline. As we increase our production in response to higher product demand or in anticipation of potential regulatory approvals, our current manufacturing capacity will likely not be sufficient, and our dependence on our collaborators and/or contract manufacturers may increase, to produce adequate quantities of drug material for both commercial and clinical purposes.

•Expanding our manufacturing capacity and establishing fill/finish capabilities has been and will continue to be costly and we may be unsuccessful in doing so in a timely manner, which could delay or prevent the launch and successful commercialization of our products approved for marketing and could jeopardize our clinical development programs.

•Our ability to manufacture products may be impaired if any of our or our collaborators' manufacturing activities, or the activities of other third parties involved in our manufacture and supply chain, are found to infringe patents of others.

•If sales of our marketed products do not meet the levels currently expected, or if the launch of any of our product candidates is delayed or unsuccessful, we may face costs related to excess inventory or unused capacity at our manufacturing facilities and at the facilities of third parties or our collaborators.

•Third-party service or supply failures, failures at our manufacturing facilities in Rensselaer, New York and Limerick, Ireland, or failures at the facilities of any other party participating in the supply chain would adversely affect our ability to supply our products.

•Our or our collaborators' or contract manufacturers' failure to meet the stringent requirements of governmental regulation in the manufacture of drug products or product candidates could result in incurring substantial remedial costs, delays in the development or approval of our product candidates or new indications for our marketed products and/or in their commercial launch if regulatory approval is obtained, and a reduction in sales.

Other Regulatory and Litigation Risks

•If the testing or use of our products harms people, or is perceived to harm them even when such harm is unrelated to our products, we could be subject to costly and damaging product liability claims.

•Our business activities have been, and may in the future be, challenged under U.S. federal or state and foreign healthcare laws, which may subject us to civil or criminal proceedings, investigations, or penalties.

•If we fail to comply with our reporting and payment obligations under the Medicaid Drug Rebate program or other governmental pricing programs, we could be subject to additional reimbursement requirements, penalties, sanctions, and fines.

•We face risks from the improper conduct of our employees, agents, contractors, or collaborators, including those relating to potential non-compliance with relevant laws and regulations such as the Foreign Corrupt Practices Act and the U.K. Bribery Act.

•Our operations are subject to environmental, health, and safety laws and regulations, including those governing the use of hazardous materials.

•Changes in laws, regulations, and policies affecting the healthcare industry could adversely affect our business.

•Tax liabilities, tariffs and other trade restrictions, and other risks associated with our operations outside the United States could adversely affect our business.

•We face risks related to the personal data we collect, process, and share.

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Risks Related to Our Reliance on or Transactions with Third Parties

•If our collaborations with Sanofi or Bayer or other third parties are terminated or breached, our ability to develop, manufacture, and commercialize certain of our products and product candidates in the time expected, or at all, may be materially harmed.

•Our collaborators and service providers may fail to perform adequately in their efforts to support the development, manufacture, and commercialization of our drug candidates and current and future products.

•We have undertaken and may in the future undertake strategic acquisitions, and any difficulties from integrating such acquisitions or failure to realize the expected benefits from such acquisitions could adversely affect our business, operating results, and financial condition.

Other Risks Related to Our Business and Our Common Stock

•Our business is dependent on our key personnel and will be harmed if we cannot recruit or retain key members of our senior management team, including leaders in our research, development, manufacturing, and commercial organizations.

•Significant disruptions of information technology systems or breaches of data security could adversely affect our business.

•Public health outbreaks, epidemics, or pandemics have adversely affected and may in the future adversely affect our business.

•Our indebtedness could adversely impact our business.

•Our stock price is extremely volatile.

•Our existing shareholders may be able to exert substantial influence over matters requiring shareholder approval and over our management.

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Risks Related to Commercialization of Our Marketed Products, Product Candidates, and New Indications for Our Marketed Products

We are substantially dependent on the success of EYLEA HD, EYLEA, and Dupixent.

We are substantially dependent on the success of EYLEA HD and EYLEA. Net product sales of these products have historically represented a substantial portion of our revenues, and we expect this concentration of our net sales to continue in the future with an increasing dependence on EYLEA HD relative to our historical dependence on EYLEA. For the years ended December 31, 2025 and 2024, our aggregate EYLEA HD and EYLEA net product sales in the United States represented 31% and 42% of our total revenues, respectively. For the year ended December 31, 2025, EYLEA HD U.S. net product sales represented 37% of our aggregate EYLEA HD and EYLEA U.S. net product sales. If we experience difficulty with the commercialization of EYLEA HD or EYLEA in the United States or if Bayer experiences any difficulty with the commercialization of EYLEA HD or EYLEA outside the United States, if EYLEA HD net product sales do not sufficiently offset any sustained decline of EYLEA net product sales in or outside the United States, or if we and Bayer are unable to maintain or obtain marketing approvals of these products (as applicable), we may experience a reduction in revenue and may not be able to stay profitable at the levels we previously achieved or at all, and our business, prospects, operating results, and financial condition may be materially harmed.

Commercialization of EYLEA HD and EYLEA in the United States and elsewhere is subject to significant competition (as described further below under "The commercial success of our products and product candidates is subject to significant competition"), which we expect to continue to increase in the future. For the year ended December 31, 2025, EYLEA U.S. net product sales declined by 42% compared to the corresponding period in 2024 as a result of competitive pressures and other factors described under Part II, Item 7. "Management's Discussion and Analysis of Financial Condition and Results of Operations – Results of Operations." Following the expiration of the U.S. regulatory exclusivity period for EYLEA in May 2024, several biosimilar versions of EYLEA have been approved by the FDA, and one such product has launched in the United States. EYLEA and/or EYLEA HD net product sales recorded by us are likely to continue to be negatively impacted by biosimilar competition in the United States, including competition from additional biosimilar versions of EYLEA expected to launch in the United States in the second half of 2026, which may have a material adverse impact on our results of operations. In addition, we expect that competition for EYLEA and/or EYLEA HD outside the United States will continue to increase as biosimilar versions of EYLEA (including those already approved but not yet launched) are brought to market in additional countries, which may negatively impact the amount of collaboration revenue we earn from Bayer. While the FDA recently approved EYLEA HD for the treatment of RVO and for an every 4-week dosing regimen across approved indications and we continue to work toward FDA approval of the EYLEA HD pre-filled syringe as discussed under Part I, Item 1. "Business - Programs in Clinical Development - Additional Information - Clinical Development Programs - EYLEA HD," there can be no assurance that such milestones (including potential FDA approval of the EYLEA HD pre-filled syringe) will help accelerate any potential future growth of EYLEA HD net product

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sales. The degree to which EYLEA HD net product sales may offset further potential decreases in EYLEA net product sales, resulting from the factors discussed above or otherwise, is uncertain.

We also are substantially dependent on our share of profits from the commercialization of Dupixent under our collaboration with Sanofi (the "Antibody Collaboration"). For the years ended December 31, 2025 and 2024, Sanofi collaboration revenue (most of which is attributable to our share of profits from the commercialization of Dupixent) represented 41% and 32% of our total revenues, respectively. If we or Sanofi were to experience any difficulty with the commercialization of Dupixent or if we or Sanofi are unable to maintain current marketing approvals of Dupixent, we may experience a reduction in revenue and our business, prospects, operating results, and financial condition may be materially harmed.

If we or our collaborators are unable to continue to successfully commercialize our products, our business, prospects, operating results, and financial condition will be materially harmed.

We expect that the degree of commercial success of our marketed products will continue to depend on many factors, including the following (as applicable):

•effectiveness of the commercial strategy in and outside the United States for the marketing of our products, including pricing strategy;

•sufficient coverage of, and reimbursement or copay assistance for, our marketed products by third-party payors and other third parties, including Medicare and Medicaid in the United States and other government and private payors in the United States and foreign jurisdictions, as well as U.S. and foreign payor restrictions on eligible patient populations and the reimbursement process (including drug price control measures that have been or may be enacted or introduced in the United States by various federal and state authorities);

•our ability and our collaborators' ability to maintain sales of our marketed products in the face of competitive products and to differentiate our marketed products from competitive products, including as applicable product candidates currently in clinical development; and, in the case of EYLEA HD and EYLEA, the existing and potential new branded and biosimilar competition (discussed further under "The commercial success of our products and product candidates is subject to significant competition - Marketed Products" below) and the willingness of retinal specialists and patients to start or continue treatment with such products or to switch from a competitive product to one of our products;

•the safety and efficacy of our marketed products seen in a broader patient group (i.e., real-world use);

•the effect of existing and new healthcare laws and regulations currently being considered or implemented in the United States and globally, including measures requiring the U.S. government in the future to negotiate the prices of certain drugs and price reporting and other disclosure requirements and the potential impact of such requirements on physician prescribing practices and payor coverage;

•serious complications or side effects in connection with the use of our marketed products, as discussed under "Risks Related to Maintaining Approval of Our Marketed Products and the Development and Obtaining Approval of Our Product Candidates and New Indications for Our Marketed Products - Serious complications or side effects in connection with the use or development of our products or product candidates could cause our regulatory approvals to be revoked or limited or lead to delay or discontinuation of development of our product candidates or new indications for our marketed products, which could severely harm our business, prospects, operating results, and financial condition" below;

•maintaining and successfully monitoring commercial manufacturing arrangements for our marketed products with third parties who perform fill/finish and bulk product manufacturing or other steps in the manufacture of such products to ensure that they meet our standards and those of regulatory authorities, including the FDA, which extensively regulate and monitor, and have been increasing their focus on, pharmaceutical manufacturing facilities;

•our ability to meet the demand for commercial supplies of our marketed products;

•the outcome of the pending proceedings relating to EYLEA (described further in Note 16 to our Consolidated Financial Statements included in this report), as well as other risks relating to our marketed products and product candidates associated with intellectual property of other parties and pending or future litigation relating thereto (as discussed under "Risks Related to Intellectual Property and Market Exclusivity" below);

•the outcome of the pending government proceedings and investigations and other matters described in Note 16 to our Consolidated Financial Statements included in this report (including the civil proceedings initiated or joined by the U.S. Department of Justice and the U.S. Attorney's Office for the District of Massachusetts); and

•the results of post-approval studies, whether conducted by us or by others and whether mandated by regulatory agencies or voluntary, and studies of other products that could implicate an entire class of products or are perceived to do so.

More detailed information about the risks related to the commercialization of our marketed products is provided in the risk factors below.

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We and our collaborators are subject to significant ongoing regulatory obligations and oversight with respect to the products we or our collaborators commercialize. If we or our collaborators fail to maintain regulatory compliance for any of such products, the applicable marketing approval may be withdrawn, which would materially harm our business, prospects, operating results, and financial condition.

We and our collaborators are subject to significant ongoing regulatory obligations and oversight with respect to the products we or they commercialize for the products' currently approved indications in the United States, EU, Japan, and other countries. If we or our collaborators fail to maintain regulatory compliance or satisfy other obligations for such products' currently approved indications (including because the product does not meet the relevant endpoints of any required post-approval studies (such as those required under an accelerated approval by the FDA or other similar type of approval), or for any of the reasons discussed below under "Risks Related to Maintaining Approval of Our Marketed Products and the Development and Obtaining Approval of Our Product Candidates and New Indications for Our Marketed Products - Obtaining and maintaining regulatory approval for drug and biologic products is costly, time-consuming, and highly uncertain. If we or our collaborators do not maintain regulatory approval for our marketed products, or obtain regulatory approval for our product candidates, we will not be able to market or sell them; and if we do not obtain approvals for new indications for our marketed products, we may not be able to realize the full commercial potential of such products. Any of the foregoing may materially and negatively impact our business, prospects, operating results, and financial condition."), the applicable marketing approval may be withdrawn, which would materially harm our business, prospects, operating results, and financial condition. Failure to comply may also subject us to sanctions, product recalls, or withdrawals of previously approved marketing applications. See also "Risks Related to Manufacturing and Supply - Our or our collaborators' or contract manufacturers' failure to meet the stringent requirements of governmental regulation in the manufacture of drug products or product candidates could result in incurring substantial remedial costs, delays in the development or approval of our product candidates or new indications for our marketed products and/or in their commercial launch if regulatory approval is obtained, and a reduction in sales" below.

Sales of our marketed products are dependent on the availability and extent of coverage and reimbursement and copay assistance from third-party payors and other third parties.

Sales of our marketed products in the United States are dependent, in large part, on the availability and extent of coverage and reimbursement from third-party payors, including private payor healthcare and insurance programs, health maintenance organizations, pharmacy benefit management companies ("PBMs"), and government programs such as Medicare and Medicaid. Such sales are also impacted by the ability of patients to afford copays and the availability and extent of copay assistance, including copay assistance provided by other third parties (such as not-for-profit patient assistance funds). Sales of our marketed products in other countries are also dependent, in large part, on complex coverage and reimbursement mechanisms and programs in those countries.

Our revenues and profitability will be materially adversely affected if such third-party payors and other third parties do not adequately defray or reimburse the cost of our marketed products. If third-party payors do not provide coverage and reimbursement with respect to our marketed products or provide an insufficient level of coverage and reimbursement, such products may be too costly for many patients to afford them, and physicians may not prescribe them. Many third-party payors cover only selected drugs, or may prefer selected drugs, making drugs that are not covered or preferred by such payors more expensive for patients. Third-party payors may also require prior authorization for reimbursement, require failure on another type of treatment, or impose other utilization management restrictions before covering a particular drug, particularly with respect to higher-priced drugs. Further, sales of our marketed products (such as EYLEA HD and EYLEA) in the United States may be adversely impacted by the lack of sufficient copay assistance from not-for-profit patient assistance funds. For example, a loss in market share to compounded bevacizumab due to patient affordability constraints impacted U.S. net product sales of EYLEA for the year ended December 31, 2025, as further described under Part II, Item 7. "Management's Discussion and Analysis of Financial Condition and Results of Operations – Results of Operations." If independent not-for-profit patient assistance funds that provide patient copay assistance are unable to support eligible patients, this will likely have a continued negative impact on patient affordability resulting in lower utilization of higher-cost anti-VEGF agents.

As our currently marketed products and most of our product candidates are biologics, bringing them to market may cost more than bringing traditional, small-molecule drugs to market due to the complexity associated with the research, development, production, supply, and regulatory review of such products. Given cost sensitivities in many healthcare systems, our currently marketed products and product candidates are likely to be subject to continued pricing pressures, which may have an adverse impact on our business, prospects, operating results, and financial condition.

In addition, in order for private insurance and governmental payors (such as Medicare and Medicaid in the United States) to reimburse the cost of our marketed products, we must maintain, among other things, our FDA registration and our National Drug Code, formulary approval by PBMs, and recognition by insurance companies and CMS. There is no certainty that we will be able

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to obtain or maintain the applicable requirements for reimbursement (including relevant formulary coverage, as discussed further below) of our current and future marketed products, which may have a material adverse effect on our business.

In addition, PBMs and other managed-care organizations often develop formularies to reduce their cost for medications. The breadth of the products covered by formularies varies considerably from one PBM to another. Failure to be included in such formularies or to achieve favorable formulary status may negatively impact the utilization and market share of our marketed products. If our marketed products are not included within an adequate number of formularies, adequate reimbursement levels are not provided, the eligible insured patient population for our products is limited, or a key payor refuses to provide reimbursement for our products in a particular jurisdiction altogether, this could have a material adverse effect on our and our collaborators' ability to commercialize the applicable product.

In many countries outside the United States, pricing, coverage, and level of reimbursement of prescription drugs are subject to governmental control, and we and our collaborators may be unable to obtain coverage, pricing, and/or reimbursement on terms that are favorable to us or necessary for us or our collaborators to successfully commercialize our marketed products in those countries. In some of these countries, the proposed pricing for a drug must be approved before it may be lawfully marketed. The requirements governing drug pricing and reimbursement vary widely from country to country, and may take into account the clinical effectiveness, cost, and service impact of existing, new, and emerging drugs and treatments. For example, the EU provides options for its member states to restrict the range of medicinal products for which their national health insurance systems provide reimbursement and to control the prices of medicinal products for human use. A member state may approve a specific price for the medicinal product or it may instead adopt a system of direct or indirect limitations on the profitability of the medicinal product placed on the market. In addition, in many countries outside the United States, we or our collaborators must participate in a tender process for public procurement of our products, and any failure to obtain acceptable pricing in the tender process could adversely affect our business. Our results of operations may suffer if we or our collaborators are unable to market our products in countries outside the United States or if coverage and reimbursement for our marketed products in such countries is limited or delayed. As discussed below under "If we are unable to establish sufficient commercial capabilities outside the United States for products we intend to commercialize or co-commercialize outside the United States, our business, prospects, operating results, and financial condition may be adversely affected," we will need to manage these and other commercialization-related risks in order for us to successfully maintain and/or further develop sufficient commercial capabilities outside the United States.

Product reimbursement and coverage policies and practices, pricing regulations and requirements, and our pricing strategy could change due to various factors beyond our control, which may adversely impact our business, prospects, operating results, and financial condition.

Government and other third-party payors (including PBMs) are challenging the prices charged for healthcare products and increasingly limiting, and attempting to limit, both coverage and level of reimbursement for prescription drugs, such as by requiring outcomes-based or other pay-for-performance pricing arrangements. They are also imposing restrictions on eligible patient populations and the reimbursement process, including by means of required prior authorizations and utilization management criteria, such as step therapy (i.e., requiring the use of less costly medications before more costly medications are approved for coverage). Private payor healthcare and insurance providers, health maintenance organizations, and PBMs are increasingly requiring significant discounts and rebates from manufacturers as a condition to including products on formulary with favorable coverage and copayment/coinsurance. In addition, many payors continue to adopt benefit plan changes that shift a greater portion of prescription costs to patients, including more limited benefit plan designs, higher patient copay or coinsurance obligations, and limitations on patients' use of commercial manufacturer copay payment assistance programs (including through copay accumulator adjustment or maximization programs). Some states have also enacted or are considering legislation to control the prices and reimbursement of prescription drugs, including by establishing Prescription Drug Affordability Boards (or similar entities) to review high-cost drugs, setting upper payment limits, and/or implementing marketing cost disclosure and transparency measures. Additionally, state Medicaid programs have been increasingly requesting that manufacturers, including Regeneron, pay supplemental rebates and requiring prior authorization by the state program for use of any prescription drug for which supplemental rebates are not being paid. It is likely that federal and state legislatures and health agencies will continue to focus on additional healthcare reform measures in the future that will impose additional constraints on prices and reimbursements for our marketed products.

Further, there have been several recent U.S. Congressional inquiries, executive orders, and recently approved or proposed federal and state legislation, regulations, and policies (in addition to those already in effect) designed to, among other things, bring more transparency to drug pricing, review the relationship between pricing and manufacturer patient programs, reduce the out-of-pocket cost of prescription drugs, and reform government program reimbursement methodologies for drugs. Notably, in 2022 the U.S. Congress passed the Inflation Reduction Act ("IRA"), which includes, among other items, provisions regarding the following:

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•Implementation of a Medicare Drug Price Negotiation Program (the "Medicare Drug Price Negotiation Program"). The Medicare Drug Price Negotiation Program requires the government to set prices for select high-expenditure drugs covered under Medicare Parts B and D. Starting in 2023 and 2026, the government is authorized to select Part D and Part B drugs, respectively, for inclusion in the Medicare Drug Price Negotiation Program, with established prices to go into effect for selected Part D drugs in 2026 and for selected Part B drugs in 2028, in each case absent certain disqualifying events.

•Medicare Inflation Based Rebates. The IRA includes measures requiring manufacturers to pay rebates where increases to the average sales price or average manufacturer price of drugs covered under Medicare Parts B and D, respectively, exceed the rate of inflation.

•Medicare Part D Program Redesign. The IRA implements changes to the Medicare Part D benefits to limit patient out-of-pocket drug costs and shift program liabilities from patients to other stakeholders, including health plans, manufacturers, and the government.

The full extent to which the policy changes described above will ultimately impact reimbursement levels of our marketed products, including those covered under Medicare Part B (such as EYLEA HD and EYLEA), or our product candidates that may be covered under Medicare Part B or Medicare Part D in the future, is currently unclear. In addition, the current U.S. administration is pursuing other measures to reduce the cost of drugs in the United States. For example, in May 2025, an executive order directed the U.S. Department of Health and Human Services ("HHS") and other federal agencies to take certain steps intended to, among other things, reduce the prices of drugs sold in the United States to match the lowest price available for the same drugs in comparably developed nations (commonly referred to as "most-favored-nation" ("MFN") pricing). In July 2025, as a follow-up to this executive order, President Trump sent a letter to several pharmaceutical companies (including Regeneron) requesting that within the next 60 days they, among other matters, provide their existing drugs at MFN rates to Medicaid patients, guarantee MFN pricing for newly launched drugs, and provide for direct-to-consumer and direct-to-business distribution models for high-volume, high-rebate prescription drugs. In addition, a prior executive order from April 2025 directed the HHS to take appropriate steps to, among other things, modify certain provisions of the Medicare Drug Price Negotiation Program, develop and implement a payment model to reduce the price of high-cost prescription drugs and biological products covered by Medicare, accelerate approval of generic and biosimilar products, and facilitate the ability of states to import pharmaceuticals from other countries. In response to these executive orders, in December 2025, the Center for Medicare and Medicaid Innovation proposed two mandatory Medicare payment models that, if enacted into law, would apply to certain drugs covered under Medicare Parts B and D and test whether alternative methodologies for calculating inflationary rebates based on international reference pricing would reduce Medicare spending. It is currently unclear how and to what extent the measures described in this paragraph may be implemented and what impact any such implementation would have on our Company.

At the state level, legislatures are becoming increasingly aggressive in passing legislation and implementing regulations designed to control pharmaceutical and biological product pricing, including price or patient reimbursement constraints, discounts, restrictions on certain product access, price and marketing cost disclosure and transparency measures, and measures that could expand the applicability of the ceiling price under the federal government's 340B program (see also "Other Regulatory and Litigation Risks - If we fail to comply with our reporting and payment obligations under the Medicaid Drug Rebate program or other governmental pricing programs, we could be subject to additional reimbursement requirements, penalties, sanctions, and fines, which could have a material adverse effect on our business, financial condition, results of operations, and future prospects."). In some cases, these measures are designed to encourage importation from other countries and bulk purchasing. A reduction in the availability or extent of reimbursement from U.S. government programs (including as a result of the legislation, proposals, initiatives, and developments described above) could have a material adverse effect on the sales of our marketed products. Economic pressure on state budgets may also have a similar impact.

The commercial success of our products and product candidates is subject to significant competition.

Marketed Products

We face substantial competition from pharmaceutical and biotechnology companies. Many of our competitors have substantially greater research, preclinical and clinical product development, and manufacturing capabilities, as well as financial, marketing, and human resources, than we do. Our competitors, regardless of their size, may also enhance their competitive position if they acquire or discover patentable inventions, form collaborative arrangements, or merge with other pharmaceutical or biotechnology companies. There is significant actual and potential future competition for each of our marketed products.

EYLEA HD and EYLEA. EYLEA HD and EYLEA face significant competition in the marketplace. For example, each of EYLEA HD and EYLEA competes in one or more of its approved indications with other VEGF inhibitors. These include Genentech/Roche's Vabysmo® (faricimab-svoa) and Susvimo® (ranibizumab ocular implant); Novartis and Genentech/Roche's Lucentis® (ranibizumab); Novartis' Beovu® (brolucizumab); and a biosimilar version of Lucentis commercialized in the United States by Biogen Inc. In addition, biosimilar versions of EYLEA have been approved and/or launched both in and outside the United States, including Amgen's PavbluTM (aflibercept-ayyh) (launched in the United States in the fourth quarter of 2024). We are aware of

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REGN US Equity

REGN · 10-K · period ended 2025-12-31

Item 1. Business

Item 1A. Risk Factors

REGN US Equity☆

REGN · 10-K · period ended 2025-12-31

Item 1. Business

Item 1A. Risk Factors

REGN US Equity