Pozelimab

Pasatru is the first and only FDA-approved treatment demonstrating reductions in both new HO lesions and clinician-assessed flare-ups, per results of a 56-week placebo-controlled trial in adults with FOP Late-breaking data presented at ASBMR show sustained efficacy of Pasatru and a consistent safety pro weeks 56 to 84, supporting long-term disease control TARRYTOWN, N.Y., Oct. 12, 2026 (GLOBE NEWSWIRE) -- Regeneron Pharmaceuticals, Inc. (NASDAQ: REGN) today announced positive 84-week results from the Phase 3 OPTIMA trial evaluating Pasatru™ (garetosmab-grts) in adults with fibrodysplasia ossificans progressiva (FOP). These longer-term findings for Pasatru demonstrated sustained efficacy in halting new, rogue bone growth and in significantly reducing disease flare-ups, and were presented during a late-breaking oral session at the American Society for Bone and Mineral Research (ASBMR) Annual Meeting. Pasatru was recently approved by the U.S. Food and Drug Administration (FDA) based on a 56-week, placebo-controlled trial to reduce the formation of new heterotopic ossification (HO) lesions and clinician-assessed flare-ups in adults with FOP. Pasatru is a VelocImmune ® -derived, fully human monoclonal antibody that binds to and inhibits signaling by the Activin A protein, which Regeneron scientists discovered to be a critical protein involved in the development of HO lesions in people with FOP. “FOP is a devastating, relentless condition in which every flare-up can bring anxiety around potential new, abnormal bone growth and resulting loss of mobility,” said Professor Richard Keen, Director of the Metabolic Bone Disease Centre, Royal National Orthopaedic Hospital, London, and global primary investigator of the OPTIMA trial. “What patients urgently need is long-term control over new HO lesions and flare-ups to help bring peace of mind. The 84-week data from the Phase 3 OPTIMA trial demonstrate sustained disease-modifying control alongside a generally well-tolerated safety profile, which is important for the adult FOP community.” OPTIMA, a global, multi-center, randomized, double-blind, placebo-controlled trial, enrolled 63 people with FOP aged 18 years and older. Trial participants were randomized to receive intravenously administered Pasatru 10 mg/kg, Pasatru 3 mg/kg, or placebo once every four weeks for 56 weeks. Following this, 58 participants completed the double-blind extension phase to at least 84 weeks. At 56 weeks, OPTIMA met its primary endpoint, demonstrating a 90% or greater reduction in new HO lesions, with a dramatic reduction in clinician-assessed flare-ups in adults with FOP. Detailed results on these 56-week data were recently published in The Lancet . The endpoints were then re-assessed at 84 weeks. From week 56, there were no new HO lesions observed at week 84 for Pasatru compared to 9 new lesions for placebo as assessed by computed tomography (CT) scan. Additionally, one new HO lesion previously detected at week 56 for Pasatru 3 mg/kg was no longer detectable at week 84. The number of new clinician-assessed flare-ups was also reduced compared to placebo, notably with 1 observed for Pasatru 10 mg/kg, 14 for Pasatru 3 mg/kg, and 17 for placebo. Through week 84, both doses of Pasatru had a generally well-tolerated safety profile, consistent with that observed at 56 weeks. At 56 weeks, the most common adverse reactions occurring in ≥10% of adults with FOP treated with Pasatru were abscess, acne, increased hair growth, madarosis (hair loss of eyebrows or lashes), oral ulcers, epistaxis (nosebleeds), folliculitis, paronychia (nail infection), and rash. At 84 weeks, the most common treatment-emergent adverse events were acne in participants treated with Pasatru 10 mg/kg and epistaxis (all non-severe) in participants treated with Pasatru 3 mg/kg. Treatment-emergent bleeding events were lower in participants treated with Pasatru 10 mg/kg than those treated with Pasatru 3 mg/kg or placebo. There was a dose-dependent increase in skin and soft tissue infections (33% on placebo, 53% on Pasatru 3 mg/kg, and 78% on Pasatru 10 mg/kg) that were all resolved with further management, with no patients discontinuing treatment as a result of infection. No deaths were reported in the trial. A Phase 3 trial of Pasatru in adolescents and children with FOP, OPTIMA 2, is planned to begin later this year. For more information, visit the Regeneron clinical trials website , contact clinicaltrials@regeneron.com , or call +1 844-734-6643. About FOP FOP is an ultra-rare genetic disorder in which muscle, ligaments, and connective tissue are progressively infiltrated by rogue bone formation, a process known as HO. HO of the jaw, spine, hip, and rib cage can make basic actions such as speaking, eating, walking, or breathing difficult, leading to skeletal deformity, weight loss, and escalating loss of mobility. Worldwide, approximately 900 people are known to have been diagnosed with FOP, and most patients become wheelchair users by age 30, with the median age of survival being approximately 56. About the OPTIMA Clinical Trial OPTIMA is a Phase 3, multi-center, multinational trial to assess the efficacy of Pasatru on the reduction of heterotopic bone formation and flares, as well as its safety, tolerability, and pharmacokinetics, in patients with active FOP. The trial enrolled 63 participants aged 18 years and older who have any FOP-causing variant of type I Activin A receptor (ACVR1), exhibited FOP disease activity or progression of HO lesions, and had a cumulative analogue joint involvement scale (CAJIS) score at screening of ≤19. CAJIS is a scoring tool used by clinicians to assess the degree of joint involvement, with higher scores representing a greater degree of disease severity (scale: 0 to 30). Eligible participants were randomized to receive intravenously administered Pasatru 10 mg/kg, Pasatru 3 mg/kg, or placebo once every four weeks for 56 weeks. Following this, participants could then elect to continue their originally assigned treatment in a double-blind extension phase for at least 84 weeks or discontinue treatment and enter an observation-only arm. During the treatment period, efficacy was evaluated through whole body CT scans for HO lesions, physician and patient assessment of flare-ups, utilization of CAJIS to rate joint functionality, and observances of change in disease severity. The safety assessment includes reports of adverse events, measurement of vital signs, physical examination, and coagulation testing. About Pasatru Regeneron has been engaged in FOP research for decades and helped to provide fundamental insights into the biology and natural history of the disease. Regeneron scientists discovered that  Activin A plays a key role in FOP  by driving HO, the main pathology of FOP . Pasatru is a  VelocImmune -derived, fully human monoclonal antibody that binds to and inhibits signaling by the Activin A protein, which is involved in the development of heterotopic bone in people with FOP. Pasatru is FDA-approved in the U.S. to reduce formation of new HO lesions and clinician-assessed flare-ups in adults with FOP. In the European Union, a regulatory submission for Pasatru is currently under review by the European Medicines Agency. Additional regulatory submissions are planned in countries around the world, including Japan. Pasatru previously received Fast Track designation and Orphan Drug Designation from the FDA, as well as Orphan Designation by the European Medicines Agency in the European Union and the Ministry of Health, Labour and Welfare in Japan. Regeneron is committed to supporting people living with rare diseases. Regeneron’s myRARE™ program offers resources to help patients and healthcare providers, including product information, insurance benefit verification, and information about potential financial support. To learn about myRARE, visit myRARE.com or call 1-833-4my-RARE (1-833-469-7273). IMPORTANT SAFETY INFORMATION What is the most important information I should know about PASATRU? PASATRU can cause serious side effects, including: Harm to your unborn baby, including serious birth defects if taken during pregnancy. Females who are pregnant must not take PASATRU. Females who can become pregnant: Your healthcare provider will ask you to take a pregnancy test to verify that you are not pregnant before starting treatment with PASATRU. Use effective birth control (contraception) during treatment with PASATRU and for 6 months after the last dose of PASATRU. Talk to your healthcare provider about birth control methods that may be right for you. If you become pregnant or think you may be pregnant during treatment with PASATRU, stop taking PASATRU immediately and call your healthcare provider right away . Infections of the skin and tissue under the skin requiring treatment or hospitalization, such as infected lumps (abscesses) and bacterial skin infections (cellulitis), may happen while you are taking PASATRU. Call your healthcare provider right away if you have signs or symptoms of skin infection, such as: • redness • pain or tenderness • skin feels warm to the touch • fever • swelling • feeling generally unwell Nosebleeds (epistaxis), including serious nosebleeds that require medical care, can happen while taking PASATRU. Tell your healthcare provider right away if you have a nosebleed that: is severe or heavy does not stop with basic first-aid measures, such as pinching your nose with continuous firm pressure lasts more than 20 minutes Do not receive PASATRU if you are pregnant. Before you receive PASATRU, tell your healthcare provider about all your medical conditions, including if you: are breastfeeding. It is not known whether PASATRU passes into your breastmilk. Breastfeeding is not recommended during treatment with PASATRU and for 6 months after the last dose of PASATRU. Talk to your healthcare provider about the best way to feed your baby during this time. are concerned about male fertility. PASATRU may affect your ability to father a child. Talk to your healthcare provider if this is concern for you. Tell your healthcare provider about all of the medicines you take, including prescription and over-the-counter medicines, vitamins, and herbal supplements. The most common side effects of PASATRU include: • infected lumps (abscess) • hair loss of eyebrows or lashes (madarosis) • acne • mouth sores (oral ulcers) • increased hair growth • nosebleeds (epistaxis) These are not all of the possible side effects of PASATRU. Call your doctor for medical advice about side effects. You may report side effects to FDA at 1-800-FDA-1088. What is PASATRU? PASATRU™ (garetosmab-grts) is a prescription medicine used to reduce the formation of new abnormal bone growth outside of the skeleton (heterotopic ossification) and flare-ups in adults with fibrodysplasia ossificans progressiva (FOP). It is not known if PASATRU is safe and effective in children. Please click here for full Prescribing Information , including Medication Guide . About Regeneron’s VelocImmune Technology Regeneron’s VelocImmune technology utilizes a proprietary genetically engineered mouse platform endowed with a genetically humanized immune system to produce fully optimized human antibodies. When Regeneron’s Co-Founder, President and Chief Scientific Officer George D. Yancopoulos was a graduate student with his mentor, Frederick W. Alt in 1985, they were the first to envision making such a genetically humanized mouse, and Regeneron has spent decades inventing and developing VelocImmune and related VelociSuite ® technologies. Dr. Yancopoulos and his team have used VelocImmune technology to create a substantial proportion of all original, FDA-approved fully human monoclonal antibodies. This includes Dupixent ® (dupilumab), Libtayo ® (cemiplimab-rwlc), Praluent ® (alirocumab), Kevzara ® (sarilumab), Evkeeza ® (evinacumab-dgnb), Inmazeb ® (atoltivimab, maftivimab and odesivimab-ebgn), Veopoz ® (pozelimab-bbfg), and Pasatru™ (garetosmab-grts). In addition, REGEN-COV ® (casirivimab and imdevimab) had been authorized by the FDA during the COVID-19 pandemic until 2024. A total of 11 antibody and bispecific products have been approved or authorized worldwide that were invented or derived using VelocImmune technologies. About Regeneron Regeneron (NASDAQ: REGN) is a leading biotechnology company that invents, develops, and commercializes life-transforming medicines for people with serious diseases. Founded and led by physician-scientists, our unique ability to repeatedly and consistently translate science into medicine has led to numerous approved treatments and product candidates in development, most of which were homegrown in our laboratories. Our medicines and pipeline 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. Regeneron pushes the boundaries of scientific discovery and accelerates drug development using our proprietary technologies, such as VelociSuite , which produces optimized fully human antibodies and new classes of bispecific antibodies. We are shaping the next frontier of medicine with data-powered insights from the Regeneron Genetics Center ® and pioneering genetic medicine platforms, enabling us to identify innovative targets and complementary approaches to potentially treat or cure diseases. For more information, please visit or follow Regeneron on LinkedIn , Instagram , Facebook or X . Forward-Looking Statements and Use of Digital Media This press release includes forward-looking statements that involve risks and uncertainties relating to future events and the future performance of Regeneron Pharmaceuticals, Inc. (“Regeneron” or the “Company”), 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, the nature, timing, and possible success and therapeutic applications of 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”) and research and clinical programs now underway or planned, including without limitation Pasatru™ (garetosmab-grts) for the treatment of adults with fibrodysplasia ossificans progressiva (“FOP”); uncertainty of the utilization, market acceptance, and/or commercial success of Regeneron’s Products (such as Pasatru) and Regeneron’s Product Candidates and the impact of studies (whether conducted by Regeneron or others and whether mandated or voluntary), including the studies discussed or referenced in this press release, on any of the foregoing; 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 Pasatru for the treatment of adolescents and children with FOP; the ability of Regeneron’s collaborators, licensees, 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 ability of Regeneron to manage supply chains for multiple products and product candidates and risks associated with tariffs and other trade restrictions; safety issues resulting from the administration of Regeneron’s Products (such as Pasatru) and Regeneron’s Product Candidates i n patients, including serious complications or side effects in connection with the use of Regeneron’s Products and Regeneron’s Product Candidates in clinical trials; determinations by regulatory and administrative governmental authorities which may delay or restrict Regeneron’s ability to continue to develop or commercialize Regeneron’s Products and Regeneron’s Product Candidates; ongoing regulatory obligations and oversight impacting Regeneron’s Products, research and clinical programs, and business, including those relating to patient privacy; 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 Regeneron’s pricing strategy, including in connection with Regeneron’s April 2026 agreements with the U.S. government; other changes in laws, regulations, and policies affecting the healthcare industry; competing products and product candidates (including biosimilar products) that may be superior to, or more cost effective than, Regeneron’s Products and Regeneron’s Product Candidates; the extent to which the results from the research and development programs conducted by Regeneron and/or its collaborators or licensees may be replicated in other studies and/or lead to advancement of product candidates to clinical trials, therapeutic applications, or regulatory approval; unanticipated expenses; the costs of developing, producing, and selling products; the ability of Regeneron to meet any of its financial projections or guidance and changes to the assumptions underlying those projections or guidance; the potential for any license, collaboration, or supply agreement, including Regeneron’s 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 Regeneron’s business; and risks associated with litigation and other proceedings and government investigations relating to the Company and/or its operations (including the pending civil proceedings initiated or joined by the U.S. Department of Justice and the U.S. Attorney's Office for the District of Massachusetts), 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 relating to EYLEA ® (aflibercept) Injection), the ultimate outcome of any such proceedings and investigations, and the impact any of the foregoing may have on Regeneron’s business, prospects, operating results, and financial condition. A more complete description of these and other material risks can be found in Regeneron’s filings with the U.S. Securities and Exchange Commission, including its Form 10-K for the year ended December 31, 2025 and its Form 10-Q for the quarterly period ended June 30, 2026. Any forward-looking statements are made based on management’s current beliefs and judgment, and the reader is cautioned not to rely on any forward-looking statements made by Regeneron. Regeneron does not undertake any obligation to update (publicly or otherwise) any forward-looking statement, including without limitation any financial projection or guidance, whether as a result of new information, future events, or otherwise. Regeneron uses its media and investor relations website and social media outlets to publish important information about the Company, including information that may be deemed material to investors. Financial and other information about Regeneron is routinely posted and is accessible on Regeneron's media and investor relations website ( ) and its LinkedIn page ( ). Contacts: Media Relations Ilana Yellen Tel: +1 914-330-9618 Ilana.Yellen@regeneron.com Investor Relations Mark Hudson Tel: +1 914-847-3482 Mark.Hudson@regeneron.com

Late-breaking Phase 3 C-POST data provide longer-term survival outcomes for adjuvant Libtayo ® (cemiplimab) in high-risk cutaneous squamous cell carcinoma (CSCC) after surgery and radiation Final Phase 2 analysis explores potential of Libtayo before surgery (neoadjuvant treatment) for patients with resectable CSCC New data explore inhibition of Factor XI for cancer-associated thrombosis, a leading cause of cancer death, where bleeding risk limits use of anticoagulants TARRYTOWN, N.Y., Oct. 06, 2026 (GLOBE NEWSWIRE) -- Regeneron Pharmaceuticals, Inc. (NASDAQ: REGN) today announced the presentation of new clinical research at the European Society for Medical Oncology (ESMO) Congress 2026, taking place from October 23-27 in Madrid, Spain. Highlights from the company’s 10 abstracts will cover new data and analyses from trials in cutaneous squamous cell carcinoma (CSCC), non-small cell lung cancer (NSCLC), ovarian cancer, melanoma and cancer-associated thrombosis. “At ESMO, we look forward to sharing data across a range of conditions reflecting the breadth of our research,” said Israel Lowy, M.D., Ph.D., Clinical Development Unit Head, Oncology, at Regeneron. “For the first time, we’re showcasing how our work extends beyond the treatment of cancer itself, and addresses some of the complex challenges patients face as a result of their disease. Together, these data reflect our broader commitment to advancing comprehensive cancer care for patients.” Highlights include: Adjuvant treatment with Libtayo in adults with CSCC with high risk of recurrence after surgery and radiation: Late-breaking overall survival (OS) data at approximately 3.5 years follow-up from the C-POST Phase 3 trial will provide further evidence supporting Libtayo as the standard of care in this indication. Neoadjuvant treatment with Libtayo in stage II-IV CSCC: Data include the final analysis of Phase 2 results, which represent the most mature data set in patients treated with Libtayo prior to surgery. Factor XI antibodies (cenvacibart and amrecibart) as a potential approach to reducing thrombosis in patients with cancer: Data include a Phase 2 sub-analysis and modeling in catheter-related VTE, plus an update on the Phase 3 ROXI-CAT-II trial. The full list of Regeneron presentations at ESMO are as follows:  Abstract Title Abstract Presenter Session Date/Time (CET) Skin Cancer C-POST Phase 3 trial of adjuvant cemiplimab vs. placebo for high-risk CSCC: OS update at approximately 3.5 years' median follow-up LBA: 59 Danny Rischin Sunday October 25, 10:15-11:45 A Phase 2 study of neoadjuvant cemiplimab for Stage II--IV CSCC: final analysis Poster presentation: 2490P Neil D. Gross Saturday October 24, 12:00-12:45 Long-term Overall Survival (OS) with Fianlimab (FIAN) plus Cemiplimab (Cemi) in Advanced Melanoma (aMel): Survival Follow-up of a Phase 1 Study Poster presentation: 2091P Omid Hamid Saturday October 24, 12:00-12:45 Lung Cancer Impact of objective response on PROs in patients receiving cemiplimab + chemotherapy vs. placebo + chemotherapy for aNSCLC: EMPOWER-Lung 3 Part 2 Poster presentation: 2714P Konstantin Penkov Monday October 26, 12:00-12:45 CEMI-LUNG, a European-based observational study to assess cemiplimab real world effectiveness and safety in patients with advanced non-small cell lung cancer Poster presentation: 2580P Jesus Corral Jaime Monday October 26, 12:00-12:45 Ovarian Cancer Circulating tumor DNA (ctDNA), cancer antigen 125 (CA125) and human epididymis protein 4 (HE4) associate with survival outcomes in patients with platinum-resistant ovarian cancer treated with ubamatamab Poster presentation: 1957P Jung-Yun Lee Saturday October 24, 12:00-12:45 A Phase 1/2 study of REGN5668 (ubamatamab) (mucin 16 [MUC16] × cluster of differentiation [CD]28 costimulatory bispecific antibody), in combination with other targeted therapies, in patients with recurrent ovarian cancer or endometrial cancer: Trial in progress update ePoster presentation: 1445eTiP Roisin E. O'Cearbhaill N/A Thrombosis ( cenvacibart [REGN7508] and amrecibart [REGN9933]) Phase 3 trial-in-progress evaluating cenvacibart for the treatment and secondary prevention of venous thromboembolism (VTE) in participants with solid and hematologic cancers (ROXI-CAT-II) ePoster presentation: 1534eTiP Andrés J. Muñoz N/A Sub-analysis of a Phase 2 study investigating amrecibart and cenvacibart for the prevention of contact-mediated VTE in participants with active cancer undergoing peripherally inserted central catheter (PICC) placement (ROXI-CATH) Poster presentation: 1468P Jeffrey I. Zwicker Monday October 26, 12:00-12:45 Population pharmacokinetic/pharmacodynamic modeling of REGN7508 Cat in patients with a PICC from ROXI-CATH who have active cancer supports maximal Factor XI pathway inhibition Poster presentation: 3968P Jeffrey I. Zwicker Saturday October 24, 12:00-12:45 The potential uses of neoadjuvant Libtayo in CSCC, ubamatamab, cenvacibart and amrecibart described above are investigational, and their safety and efficacy have not been evaluated by any regulatory authority. About Regeneron in Cancer We aspire to turn revolutionary discoveries into medicines that can transform the lives of those impacted by cancer. Our team around the world is driven to solve the needs and challenges of those affected by one of the most serious diseases of our time. Backed by our legacy of scientific innovation and a deep understanding of biology, genetics and the immune system, we’re pursuing potential therapies across more than 30 types of solid tumors and blood cancers. Our cancer strategy is powered by cutting-edge technologies and therapies that can be flexibly combined to investigate potentially transformative treatments for patients. Oncology assets in clinical development comprise nearly half of Regeneron’s pipeline, and include checkpoint inhibitors, bispecific antibodies and costimulatory bispecific antibodies. Our approved PD-1 inhibitor Libtayo serves as the backbone of many of our investigational combinations. To complement our extensive in-house capabilities, we collaborate with patients, healthcare providers, governments, biopharma companies and each other to further our shared goals. Together, we are united in the mission to serve as a beacon of transformation in cancer care. About Libtayo Libtayo is a fully human monoclonal antibody targeting the immune checkpoint receptor PD-1 on T cells and was invented using Regeneron's proprietary VelocImmune ® technology. By binding to PD-1, Libtayo has been shown to block cancer cells from using the PD-1 pathway to suppress T-cell activation. Libtayo has been approved by regulatory authorities in more than 30 countries in one or more indications, including for certain adult patients with advanced basal cell carcinoma (BCC), CSCC that is advanced or at high risk of recurrence, advanced NSCLC and advanced cervical cancer. In the U.S., the generic name for Libtayo in its approved indications is cemiplimab-rwlc, with rwlc as the suffix designated in accordance with Nonproprietary Naming of Biological Products Guidance for Industry issued by the U.S. FDA. Outside of the U.S., the generic name of Libtayo in its approved indications is cemiplimab.  The extensive clinical program for Libtayo is focused on difficult-to-treat cancers. Libtayo is currently being investigated in trials as a monotherapy, as well as in combination with either conventional or novel therapeutic approaches for other solid tumors. These potential uses are investigational, and their safety and efficacy have not been evaluated by any regulatory authority.    U.S. FDA-approved Indications Libtayo is a prescription medicine used to treat: Adults with a type of skin cancer called cutaneous squamous cell carcinoma (CSCC): that has spread or cannot be cured by surgery or radiation, or to help prevent CSCC from coming back if your CSCC is at high risk of coming back after it has been removed by surgery and radiation. Adults with a type of skin cancer called basal cell carcinoma (BCC) when your BCC cannot be removed by surgery (locally advanced BCC) or when it has spread (metastatic BCC) and have received treatment with a hedgehog pathway inhibitor (HHI), or cannot receive treatment with a HHI. Adults with a type of lung cancer called non-small cell lung cancer (NSCLC). LIBTAYO may be used in combination with chemotherapy that contains a platinum medicine as your first treatment when your lung cancer has not spread outside your chest (locally advanced lung cancer) and you cannot have surgery or chemotherapy with radiation, or your lung cancer has spread to other areas of your body (metastatic lung cancer), and your tumor does not have an abnormal “EGFR,” “ALK,” or “ROS1” gene. LIBTAYO may be used alone as your first treatment when your lung cancer has not spread outside your chest (locally advanced lung cancer) and you cannot have surgery or chemotherapy with radiation, or your lung cancer has spread to other areas of your body (metastatic lung cancer), and your tumor tests positive for high “PD-L1,” and your tumor does not have an abnormal “EGFR,” “ALK,” or “ROS1” gene. It is not known if Libtayo is safe and effective in children.  IMPORTANT SAFETY INFORMATION FOR U.S. PATIENTS  What is the most important information I should know about LIBTAYO? LIBTAYO is a medicine that may treat certain cancers by working with your immune system. LIBTAYO can cause your immune system to attack normal organs and tissues in any area of your body and can affect the way they work. These problems can sometimes become severe or life-threatening and can lead to death. You can have more than one of these problems at the same time. These problems may happen anytime during treatment or even after your treatment has ended. Call or see your healthcare provider right away if you develop any new or worsening signs or symptoms, including: Lung problems: cough, shortness of breath, or chest pain Intestinal problems: diarrhea (loose stools) or more frequent bowel movements than usual, stools that are black, tarry, sticky or have blood or mucus, or severe stomach-area (abdomen) pain or tenderness Liver problems: yellowing of your skin or the whites of your eyes, severe nausea or vomiting, pain on the right side of your stomach-area (abdomen), dark urine (tea colored), or bleeding or bruising more easily than normal Hormone gland problems: headache that will not go away or unusual headaches, eye sensitivity to light, eye problems, rapid heartbeat, increased sweating, extreme tiredness, weight gain or weight loss, feeling more hungry or thirsty than usual, urinating more often than usual, hair loss, feeling cold, constipation, your voice gets deeper, dizziness or fainting, or changes in mood or behavior, such as decreased sex drive, irritability, or forgetfulness Kidney problems : decrease in your amount of urine, blood in your urine, swelling of your ankles, or loss of appetite Skin problems: rash, itching, skin blistering or peeling, painful sores or ulcers in mouth or nose, throat, or genital area, fever or flu-like symptoms, or swollen lymph nodes Problems can also happen in other organs and tissues. These are not all of the signs and symptoms of immune system problems that can happen with LIBTAYO. Call or see your healthcare provider right away for any new or worsening signs or symptoms, which may include: chest pain, irregular heartbeat, shortness of breath or swelling of ankles, confusion, sleepiness, memory problems, changes in mood or behavior, stiff neck, balance problems, tingling or numbness of the arms or legs, double vision, blurry vision, sensitivity to light, eye pain, changes in eyesight, persistent or severe muscle pain or weakness, muscle cramps, low red blood cells, or bruising Infusion reactions that can sometimes be severe or life-threatening. Signs and symptoms of infusion reactions may include: nausea, vomiting, chills or shaking, itching or rash, flushing, shortness of breath or wheezing, dizziness, feel like passing out, fever, back or neck pain, or facial swelling Rejection of a transplanted organ or tissue. Your healthcare provider should tell you what signs and symptoms you should report and monitor you, depending on the type of organ or tissue transplant that you have had Complications, including graft-versus-host disease (GVHD), in people who have received a bone marrow (stem cell) transplant that uses donor stem cells (allogeneic). These complications can be serious and can lead to death. These complications may happen if you underwent transplantation either before or after being treated with LIBTAYO. Your healthcare provider will monitor you for these complications Getting medical treatment right away may help keep these problems from becoming more serious. Your healthcare provider will check you for these problems during your treatment with LIBTAYO. Your healthcare provider may treat you with corticosteroid or hormone replacement medicines. Your healthcare provider may also need to delay or completely stop treatment with LIBTAYO if you have severe side effects. Before you receive LIBTAYO, tell your healthcare provider about all your medical conditions, including if you: have immune system problems such as Crohn’s disease, ulcerative colitis, or lupus have received an organ or tissue transplant, including corneal transplant have received or plan to receive a stem cell transplant that uses donor stem cells (allogeneic) have received radiation treatment to your chest area have a condition that affects your nervous system, such as myasthenia gravis or Guillain-Barré syndrome are pregnant or plan to become pregnant. LIBTAYO can harm your unborn baby Females who are able to become pregnant: Your healthcare provider will give you a pregnancy test before you start treatment You should use an effective method of birth control during your treatment and for at least 4 months after your last dose of LIBTAYO. Talk to your healthcare provider about birth control methods that you can use during this time Tell your healthcare provider right away if you become pregnant or think you may be pregnant during treatment with LIBTAYO are breastfeeding or plan to breastfeed. It is not known if LIBTAYO passes into your breast milk. Do not breastfeed during treatment and for at least 4 months after the last dose of LIBTAYO Tell your healthcare provider about all the medicines you take , including prescription and over-the-counter medicines, vitamins, and herbal supplements. The most common side effects of LIBTAYO when used alone to treat CSCC that has spread or cannot be cured by surgery or radiation, BCC, or NSCLC include tiredness, muscle or bone pain, rash, diarrhea, and low levels of red blood cells (anemia). The most common side effects of LIBTAYO when used alone to help prevent CSCC from coming back include rash and itching. The most common side effects of LIBTAYO when used in combination with platinum-containing chemotherapy to treat NSCLC include hair loss, muscle or bone pain, nausea, tiredness, numbness, pain, tingling, or burning in your hands or feet, and decreased appetite. These are not all the possible side effects of LIBTAYO. Call your doctor for medical advice about side effects. You may report side effects to FDA at 1-800-FDA-1088. You may also report side effects to Regeneron Pharmaceuticals at 1-877-542-8296. Please see full Prescribing Information , including Medication Guide . About Regeneron's VelocImmune ® Technology Regeneron's VelocImmune technology utilizes a proprietary genetically engineered mouse platform endowed with a genetically humanized immune system to produce optimized fully human antibodies. When Regeneron's co-Founder, President and Chief Scientific Officer George D. Yancopoulos was a graduate student with his mentor Frederick W. Alt in 1985, they were the first to envision making such a genetically humanized mouse, and Regeneron has spent decades inventing and developing VelocImmune and related VelociSuite ® technologies. Dr. Yancopoulos and his team have used VelocImmune technology to create a substantial proportion of all original, FDA-approved fully human monoclonal antibodies. This includes Dupixent ® (dupilumab), Libtayo ® (cemiplimab-rwlc), Praluent ® (alirocumab), Kevzara ® , Evkeeza ® (evinacumab-dgnb), Inmazeb ® (atoltivimab, maftivimab and odesivimab-ebgn), Veopoz ® (pozelimab-bbfg) and Pasatru™ (garetosmab-grts). In addition, REGEN-COV ® (casirivimab and imdevimab) had been authorized by the FDA during the COVID-19 pandemic until 2024. A total of 11 antibody and bispecific products have been approved or authorized worldwide that were invented or derived using VelocImmune technologies. About Regeneron Regeneron (NASDAQ: REGN) is a leading biotechnology company that invents, develops and commercializes life-transforming medicines for people with serious diseases. Founded and led by physician-scientists, our unique ability to repeatedly and consistently translate science into medicine has led to numerous approved treatments and product candidates in development, most of which were homegrown in our laboratories. Our medicines and pipeline 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. Regeneron pushes the boundaries of scientific discovery and accelerates drug development using our proprietary technologies, such as VelociSuite ® , which produces optimized fully human antibodies and new classes of bispecific antibodies. We are shaping the next frontier of medicine with data-powered insights from the Regeneron Genetics Center ® and pioneering genetic medicine platforms, enabling us to identify innovative targets and complementary approaches to potentially treat or cure diseases. For more information, please visit or follow Regeneron on LinkedIn , Instagram , Facebook or X . Forward-Looking Statements and Use of Digital Media This press release includes forward-looking statements that involve risks and uncertainties relating to future events and the future performance of Regeneron Pharmaceuticals, Inc. (“Regeneron” or the “Company”), 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, the nature, timing, and possible success and therapeutic applications of 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”) and research and clinical programs now underway or planned, including without limitation Libtayo ® (cemiplimab) as an adjuvant or neoadjuvant treatment for high-risk cutaneous squamous cell carcinoma, Regeneron’s Factor XI antibodies (cenvacibart and amrecibart) as a potential approach to reducing thrombosis in patients with cancer, and the other clinical programs discussed or referenced in this press release; the likelihood, timing, and scope of possible regulatory approval and commercial launch of Regeneron’s Product Candidates and new indications for Regeneron’s Products, such as those referenced above; uncertainty of the utilization, market acceptance, and/or 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), including the studies discussed or referenced in this press release, on any of the foregoing or any potential regulatory approval of Regeneron’s Products and Regeneron’s Product Candidates (such as those referenced above); the ability of Regeneron’s collaborators, licensees, 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 ability of Regeneron to manage supply chains for multiple products and product candidates and risks associated with tariffs and other trade restrictions; safety issues resulting from the administration of Regeneron’s Products and Regeneron’s Product Candidates (such as those referenced above) i n patients, including serious complications or side effects in connection with the use of Regeneron’s Products and Regeneron’s Product Candidates in clinical trials; determinations by regulatory and administrative governmental authorities which may delay or restrict Regeneron’s ability to continue to develop or commercialize Regeneron’s Products and Regeneron’s Product Candidates; ongoing regulatory obligations and oversight impacting Regeneron’s Products, research and clinical programs, and business, including those relating to patient privacy; 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 Regeneron’s pricing strategy, including in connection with Regeneron’s April 2026 agreements with the U.S. government; other changes in laws, regulations, and policies affecting the healthcare industry; competing products and product candidates (including biosimilar products) that may be superior to, or more cost effective than, Regeneron’s Products and Regeneron’s Product Candidates; the extent to which the results from the research and development programs conducted by Regeneron and/or its collaborators or licensees may be replicated in other studies and/or lead to advancement of product candidates to clinical trials, therapeutic applications, or regulatory approval; unanticipated expenses; the costs of developing, producing, and selling products; the ability of Regeneron to meet any of its financial projections or guidance and changes to the assumptions underlying those projections or guidance; the potential for any license, collaboration, or supply agreement, including Regeneron’s 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 Regeneron's business; and risks associated with litigation and other proceedings and government investigations relating to the Company and/or its operations (including the pending civil proceedings initiated or joined by the U.S. Department of Justice and the U.S. Attorney's Office for the District of Massachusetts), 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 relating to EYLEA ® (aflibercept) Injection), the ultimate outcome of any such proceedings and investigations, and the impact any of the foregoing may have on Regeneron’s business, prospects, operating results, and financial condition. A more complete description of these and other material risks can be found in Regeneron’s filings with the U.S. Securities and Exchange Commission, including its Form 10-K for the year ended December 31, 2025 and its Form 10-Q for the quarterly period ended June 30, 2026. Any forward-looking statements are made based on management’s current beliefs and judgment, and the reader is cautioned not to rely on any forward-looking statements made by Regeneron. Regeneron does not undertake any obligation to update (publicly or otherwise) any forward-looking statement, including without limitation any financial projection or guidance, whether as a result of new information, future events, or otherwise. Regeneron uses its media and investor relations website and social media outlets to publish important information about the Company, including information that may be deemed material to investors. Financial and other information about Regeneron is routinely posted and is accessible on Regeneron's media and investor relations website ( ) and its LinkedIn page ( ). Contacts: Media Relations Taylor Ramsey Skott Tel: +1 914-409-2381 taylor.ramsey@regeneron.com Investor Relations Mark Hudson Tel: +1 914-847-3482 mark.hudson@regeneron.com