Casirivimab

As published in The Lancet and presented at AAN, NIMBLE trial met its primary and key secondary endpoints at week 24, demonstrating potential best-in-class efficacy and convenience in gMG U.S. regulatory application submitted; cemdisiran could be the first siRNA to be approved for the treatment of gMG Regeneron to host virtual ‘Regeneron Roundtable: gMG & C5 Complement Program’ investor event on Wednesday, April 22 at 8:30 a.m. ET TARRYTOWN, N.Y., April 21, 2026 (GLOBE NEWSWIRE) -- Regeneron Pharmaceuticals, Inc. (NASDAQ: REGN) today announced detailed positive results from the Phase 3 NIMBLE trial evaluating investigational cemdisiran in adults with generalized myasthenia gravis (gMG) were published in The Lancet and presented for the first time in an oral plenary session at the American Academy of Neurology (AAN) Annual Meeting. Cemdisiran is a novel siRNA therapeutic that durably reduces circulating levels of complement factor 5 (C5), allowing for every three months dosing. “Generalized myasthenia gravis is a chronic debilitating disease with unpredictable symptoms that impact daily life. While current therapies have managed disease activity, there remains an unmet need for options that achieve rapid and sustained efficacy with reduced treatment burden,” said Tuan Vu, M.D., Professor of Neurology at the University of South Florida Morsani College of Medicine, Division Director for Neuromuscular Medicine and EMG Laboratories, and a global principal investigator of the NIMBLE trial.* “In the Phase 3 NIMBLE trial, this first-of-its-kind investigational therapy demonstrated rapid, robust efficacy with lasting benefit through 24 weeks. These impressive results suggest cemdisiran can represent a transformative advance in care for people living with gMG, offering compelling efficacy coupled with convenient four-times-a-year subcutaneous administration.” The NIMBLE trial results at AAN provide additional detail to the topline data shared in August 2025. As presented, and as compared to placebo (n=59), patients treated with subcutaneous cemdisiran (n=64) every twelve weeks experienced clinically meaningful improvements within two weeks on two assessment scales that measured changes from baseline in: daily functions impacted by gMG (such as talking, eating, breathing, vision and mobility) and muscle function (such as vision, speaking/swallowing, breathing and limb mobility). These improvements deepened over time across both scales and were sustained through week 24, with no indication of waning efficacy between doses. Specifically, the results for cemdisiran compared to placebo at week 24 demonstrated a: 4.5-point improvement (least squares [LS] mean change) from baseline on the Myasthenia Gravis-Activities of Daily Living (MG-ADL) total score (0.4 standard error [SE]) compared to a 2.2-point improvement (0.5 SE). This corresponded to a placebo-adjusted improvement of 2.3 points (p<0.001), meeting the primary endpoint. Notably, 76.6% of cemdisiran patients had a ≥3-point improvement, versus 44.1% for placebo. Clinically meaningful improvements in MG-ADL total score occurred within 2 weeks in cemdisiran-treated patients (-2.5-point LS mean change from baseline), which was a pre-specified exploratory endpoint. MG-ADL is a patient-reported assessment of daily functions impacted by gMG.4.2-point improvement (LS mean change) from baseline in Quantitative Myasthenia Gravis (QMG) total score (0.6 SE) compared to a 1.5-point improvement (0.7 SE). This resulted in a placebo-adjusted improvement of 2.8 points (p=0.002), meeting the key secondary endpoint. Notably, 48.4% of cemdisiran patients had a ≥5-point improvement, compared to 19% for placebo. Improvements in QMG total scores occurred within 2 weeks in cemdisiran-treated patients (-1.9-point LS mean change from baseline), which was a pre-specified exploratory endpoint. QMG is a physician-administered assessment of muscle function. Approved C5 inhibitor therapies have demonstrated in previous registrational clinical trials placebo-adjusted improvements in MG-ADL total scores ranging from -1.6 to -2.1 and in QMG total scores ranging from -2.0 to -3.0 at the time of each trial’s primary analysis (generally at week 12 or week 26). One or more treatment-emergent adverse events (AEs) occurred in 69.2% of patients receiving cemdisiran (cemdi) and 77.1% receiving placebo (pbo). Most AEs were mild-to-moderate in severity. The most common AEs (≥5%) in patients receiving cemdisiran or placebo were: worsening of MG (1% cemdi, 17% pbo), upper respiratory tract infection (12% cemdi, 11% pbo), urinary tract infection (5% cemdi, 3% pbo), nasopharyngitis (5% cemdi, 4% pbo), headache (5% cemdi, 10% pbo), rash (5% cemdi, 1% pbo), and diarrhea (3% cemdi, 7% pbo). Overall, the rates of infection during the double-blind treatment period (DBTP) were 27% in the cemdisiran group and 40% in the placebo group. No serious infections, meningococcal infections, or deaths occurred during the DBTP. There were no treatment discontinuations due to adverse events through week 24 in the cemdisiran arm compared to 3% of patients receiving placebo. Adverse events leading to dose interruption/reduction occurred in 1% and 4% of patients receiving cemdisiran and placebo, respectively. During the extension period, one death due to pneumonia occurred in the cemdisiran arm in a patient with a significant co-morbidity and also receiving concomitant immunosuppressive therapy. Rates of hospitalization, myasthenic crisis and rescue therapy were numerically lower with cemdisiran. The potential use of cemdisiran for the treatment of gMG is investigational and has not been approved by any regulatory authority. The U.S. regulatory application for cemdisiran was submitted in the first quarter of 2026; additional regulatory filings, including in the European Union, are planned for 2026. About the ‘Regeneron Roundtable: gMG & C5 Complement Program’ Investor Event Regeneron will host a virtual investor event to discuss its C5 development program on Wednesday, April 22 at 8:30 a.m. ET. This is the next webcast in a new investor event series called the ‘Regeneron Roundtable’, intended to highlight programs from the company’s innovative investigational pipeline. Links to the webcast and to register via telephone may be accessed from the ‘Investors and Media’ page of Regeneron’s website at https://investor.regeneron.com/events-and-presentations. Upon registration, all telephone participants will receive a confirmation email detailing how to join the conference call, including the dial-in number along with a unique passcode and registrant ID that can be used to access the call. A replay of the conference call and webcast will be archived on the company’s website for at least 30 days. About Myasthenia Gravis (MG)MG is a rare and chronic autoimmune disease where abnormal acetylcholine receptor (anti-AChR) antibodies activate the complement system including C5, disrupting communication between nerves and muscles that results in debilitating and potentially life-threatening muscle weakness. In the U.S., the disease impacts approximately 85,000 people. Initial manifestations are usually ocular, but approximately 85% of MG patients experience additional advancements to the disease manifestations, which is known as generalized myasthenia gravis (gMG). For these patients, the disease affects muscles throughout the body, resulting in extreme fatigue and difficulties with facial expression, speech, swallowing and mobility. Treatment-related challenges – which include frequent hospital visits, inconsistent symptom control, and lack of durable treatment effects – can further affect quality of life and long-term disease management. About the Complement Factor 5 (C5) Clinical ProgramThe largest global, interventional gMG trial conducted to date, NIMBLE is a randomized, double-blind, placebo-controlled ongoing trial evaluating cemdisiran, as well as a combination of cemdisiran and pozelimab (C5 antibody), in patients with gMG who have antibodies to the acetylcholine receptor (anti-AChR) and could continue background immunosuppressants based on the investigator’s discretion. Participants were randomized to receive one of four subcutaneous regimens: cemdisiran (600 mg) every 12 weeks; a combination of cemdisiran (200 mg) and pozelimab (200 mg) every 4 weeks; pozelimab (200 mg) every 4 weeks; or placebo every 4 weeks. The primary endpoint assessed changes in the MG-ADL total score from baseline to week 24. The MG-ADL scale is an eight-question patient-reported tool that measures how gMG affects aspects of daily life and provides a total score ranging from 0 to 24. The key secondary endpoint was the change from baseline in QMG total score at week 24. The QMG is a physician-administered 13-item standardized assessment evaluating muscle function that provides a total score ranging from 0 to 39. In both MG-ADL and QMG, a higher total score indicates greater disease severity, and a larger reduction in total score indicates greater improvement in disease symptoms and better treatment effect. Cemdisiran and pozelimab are also being evaluated in separate Phase 3 trials as both monotherapy and combination therapy for additional complement-mediated disorders, including PNH and geographic atrophy secondary to age-related macular degeneration. For more information, visit the Regeneron clinical trials website, or contact clinicaltrials@regeneron.com or +1 844-734-6643. Regeneron is solely responsible for the development, manufacturing, and commercialization of cemdisiran as a monotherapy and in combination with C5 antibodies through a worldwide licensing agreement with Alnylam. In the U.S., pozelimab monotherapy is approved as Veopoz® (pozelimab-bbfg) for adult and pediatric patients 1 year of age and older with CHAPLE disease, also known as CD55-deficient protein-losing enteropathy, which includes a Boxed Warning for life-threatening and fatal meningococcal infections. IMPORTANT SAFETY INFORMATION What is the most important information I should know about VEOPOZ?VEOPOZ is a medicine that affects your immune system and can lower the ability of your immune system to fight infections. VEOPOZ increases your chance of getting serious and life-threatening meningococcal infections that may quickly become life-threatening and cause death if not recognized and treated early. You must receive meningococcal vaccines at least 2 weeks before your first dose of VEOPOZ if you have not already had these vaccines.If you had a meningococcal vaccine in the past, you might need additional vaccination before starting VEOPOZ. Your healthcare provider will decide if you need additional meningococcal vaccination.If your healthcare provider decides that urgent treatment with VEOPOZ is needed, and your meningococcal vaccines are not up-to-date, you should receive meningococcal vaccination as soon as possible. You should also receive antibiotics.Meningococcal vaccines reduce the risk of meningococcal infection but do not prevent all meningococcal infections. Call your healthcare provider or get emergency medical care right away if you get any of these signs and symptoms of a meningococcal infection: headache with nausea or vomitingheadache with a stiff neck or stiff backfever and a rashmuscle aches with flu-like symptomsheadache and feverfeverconfusioneyes sensitive to light Your healthcare provider will give you a Patient Safety Card about the symptoms of meningococcal, or other infection. Carry it with you at all times during treatment and for 3 months after your last VEOPOZ dose. Your risk of meningococcal infection may continue for several weeks after your last dose of VEOPOZ. It is important to show this card to any healthcare provider who treats you. This will help them diagnose and treat you quickly. VEOPOZ may also increase the risk of other types of serious bacterial infections. People who take VEOPOZ may have an increased risk of getting infections caused by Streptococcus pneumoniae and Haemophilus influenzae.Certain people may also have an increased risk of bacterial infection including gonorrhea infection. Talk to your healthcare provider to find out if you are at risk of gonorrhea infection, about gonorrhea prevention, and regular testing. Call your healthcare provider right away if you have any new signs or symptoms of infection. Do not receive VEOPOZ if you have a meningococcal infection. Before you receive VEOPOZ, tell your healthcare provider about all of your medical conditions, including if you: have an infection or fever, are pregnant or plan to become pregnant, and are breastfeeding or plan to breastfeed. It is not known if VEOPOZ will harm your unborn baby or if it passes into your breast milk. Talk to your healthcare provider about the best way to feed your baby during treatment with VEOPOZ. Tell your healthcare provider about all the medicines you take, including prescription and over-the-counter medicines, vitamins, and herbal supplements. It is important that you have all recommended vaccinations before you start VEOPOZ, receive antibiotics if you start VEOPOZ within 2 weeks of receiving meningococcal vaccination, and stay up to date with all recommended vaccinations during treatment with VEOPOZ.VEOPOZ and other medicines may affect each other, causing side effects. VEOPOZ may affect the way other medicines work, and other medicines may affect how VEOPOZ works.Especially tell your healthcare provider if you take Intravenous Immunoglobulin (IVIg).Know the medicines you take and the vaccines you receive. Keep a list of them to show your healthcare provider and pharmacist when you get a new medicine. What are the possible side effects of VEOPOZ?VEOPOZ can cause serious side effects including allergic (hypersensitivity) reactions including infusion-related reactions, which may happen during your treatment. Tell your healthcare provider right away if you develop any of these symptoms or any other symptom during your VEOPOZ treatment that may mean you are having a serious allergic reaction: chest pain, trouble breathing or shortness of breath, swelling of your face, tongue, or throat, and feel faint or pass out. The most common side effects of VEOPOZ are upper respiratory tract infection, fracture, raised, red patches of skin that are often very itchy (hives), and hair loss (alopecia).Tell your healthcare provider if you have any side effect that bothers you or that does not go away. These are not all of the possible side effects of VEOPOZ. Call your healthcare provider for medical advice about side effects. You may report side effects to FDA at 1-800-FDA-1088. Please see the full Prescribing Information, including Boxed WARNING, and Medication Guide for VEOPOZ. 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 or authorized fully human monoclonal antibodies. This includes REGEN-COV® (casirivimab and imdevimab), Dupixent® (dupilumab), Libtayo® (cemiplimab-rwlc), Praluent® (alirocumab), Kevzara® (sarilumab), Evkeeza® (evinacumab-dgnb), Inmazeb® (atoltivimab, maftivimab and odesivimab-ebgn) and Veopoz® (pozelimab). 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 www.Regeneron.com or follow Regeneron on LinkedIn, Instagram, Facebook or X. Forward-Looking Statements and Use of Digital MediaThis 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 cemdisiran (an investigational siRNA therapeutic targeting C5); 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 cemdisiran for the treatment of adults with generalized myasthenia gravis as discussed in this press release as well as cemdisiran as a monotherapy or in combination with pozelimab (a C5 antibody) for the treatment of other complement-mediated disorders (including paroxysmal nocturnal hemoglobinuria and/or geographic atrophy); 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), 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 cemdisiran and pozelimab); 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 cemdisiran and pozelimab) 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; 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; 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. 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 (https://investor.regeneron.com) and its LinkedIn page (https://www.linkedin.com/company/regeneron-pharmaceuticals). *This is not an endorsement from the University of South Florida Contacts: Media RelationsTammy AllenTel: +1 914-306-2698tammy.allen@regeneron.comInvestor RelationsMark HudsonTel: +1 914-847-3482mark.hudson@regeneron.com

Approval in CSU for children 2 to 11 years of age is based on data from the LIBERTY-CUPID clinical trial program, including an extrapolation of efficacy data showing that Dupixent significantly reduced urticaria activity compared with placebo in adults The latest approval expands Dupixent’s indication for CSU in the EU to children as young as 2 years; Dupixent is now approved for children less than 12 years of age across four chronic diseases driven in part by type 2 inflammation TARRYTOWN, N.Y. and PARIS, April 13, 2026 (GLOBE NEWSWIRE) -- Regeneron Pharmaceuticals, Inc. (NASDAQ: REGN) and Sanofi today announced that the European Commission (EC) has approved Dupixent ® (dupilumab) for the treatment of moderate-to-severe chronic spontaneous urticaria (CSU) in children aged 2 to 11 years with inadequate response to histamine-1 antihistamines (H1AH) and who are naïve to anti-immunoglobulin E (IgE) therapy for CSU. This expands the previous approval in the EU for adults and adolescents aged 12 years and older with CSU, a chronic, inflammatory skin disease that causes sudden and debilitating hives and recurring itch. “Young children suffering from chronic spontaneous urticaria often experience an unpredictable barrage of unrelenting itch and visible hives during the critical years of their growth and development. As the first and only targeted medicine for young children in the EU with CSU, Dupixent has the potential to become the new standard of care for those who remain symptomatic despite other available treatments,” said George D. Yancopoulos, M.D., Ph.D., Board co-Chair, President and Chief Scientific Officer at Regeneron, and a principal inventor of Dupixent. “Dupixent is the most widely used innovative branded antibody medicine in the world, and this fourth approval for young children with chronic diseases driven in part by type 2 inflammation brings its proven efficacy and long-term safety pro yet another vulnerable population in need.” The approval in the EU is based on data from the LIBERTY-CUPID clinical trial program. This includes an extrapolation of efficacy data in adults from two Phase 3 trials ( Study A and Study C ) complemented by pharmacokinetic, safety and efficacy data from the single-arm CUPIDKids Phase 3 trial in children aged 2 to 11 years with CSU. Study A and Study C demonstrated Dupixent significantly reduced urticaria activity (a composite of itch and hives) and individual measures of itch and hive severity compared with placebo at week 24. Dupixent also increased the percentage of patients with well-controlled disease and complete response at week 24 compared with placebo. Safety results from Study A, Study C and CUPIDKids were generally consistent with the known safety pro Dupixent in its approved dermatological indications. The most common adverse reactions for Dupixent overall are injection site reactions, conjunctivitis, conjunctivitis allergic, arthralgia, oral herpes and eosinophilia. Additional adverse reactions of injection site induration, injection site dermatitis and injection site bruising or hematoma were reported in the CSU adult and adolescent trials.* The adverse event more commonly observed with Dupixent (≥5%) than placebo in Study A and Study C in adults and adolescents with CSU was COVID-19. Safety data for children aged 2 to 11 years with CSU were generally consistent with the safety pro adult and adolescent patients with CSU treated with Dupixent. “Previous treatment options for young children with chronic spontaneous urticaria left many patients with uncontrolled disease where the unpredictable appearance of itch and hives continued to disrupt their daily lives,” said Alyssa Johnsen, M.D., Ph.D., Global Therapeutic Area Head, Immunology Development at Sanofi. “Dupixent, which inhibits signaling of IL-4 and IL-13, two of the key and central drivers of type 2 inflammation, provides a first-of-its-kind approach to addressing chronic spontaneous urticaria in young children. This approval demonstrates our commitment to extending the value of Dupixent to all who may benefit, including young children.” In the U.S., the supplemental Biologics License Application (sBLA) for Dupixent has been accepted for review in certain children aged 2 to 11 years with CSU. Dupixent is currently approved for CSU in certain adults and adolescents in many jurisdictions, including the U.S. and Japan . *Adverse reactions in adults and adolescents were pooled from Study A, Study B and Study C. Study B evaluated Dupixent in patients aged 12 years and older who were inadequate responders or intolerant to anti-IgE therapy and symptomatic despite H1AH use. About CSU CSU is a chronic, inflammatory skin disease driven in part by type 2 inflammation, which causes sudden and debilitating hives and recurring itch. CSU is typically treated with H1AH, medicines that target H1 receptors on cells to control symptoms of itch and urticaria. However, the disease remains uncontrolled despite H1AH treatment in many patients, some of whom are left with limited alternative treatment options. These individuals continue to experience symptoms that can be debilitating and significantly impact their quality of life. About the Dupixent CSU Phase 3 Trial Program The LIBERTY-CUPID Phase 3 program evaluating Dupixent for CSU in children aged 2 to 11 years includes Study A, Study C and CUPIDKids. CUPIDKids was a single arm clinical trial that assessed the safety, efficacy and pharmacokinetics of Dupixent in children aged 2 to 11 years with CSU who remained symptomatic despite the use of antihistamines. During the 24-week treatment period, Dupixent was administered at 200 mg every two or four weeks or 300 mg every four weeks, with or without an initial loading dose, based on age and weight. The primary endpoint measured the serum concentration of Dupixent over time, including C trough (lowest concentration before the next dose) at week 12 and week 24. Study A and Study C were replicate, double-blind, placebo-controlled clinical trials that assessed Dupixent as an add-on therapy to standard-of-care antihistamines compared to antihistamines alone in patients aged 6 years and older who remained symptomatic despite the use of antihistamines and were naïve to anti-IgE therapy. During the 24-week treatment period in both trials, all patients received an initial loading dose followed by either 300 mg Dupixent every two weeks, or for pediatric patients weighing 30 kg to <60 kg, 200 mg every two weeks. In both trials, endpoints assessed at week 24 included: Change from baseline in itch and hives (weekly urticaria activity score [UAS7], 0-42 scale) the primary endpoint. Change from baseline in itch (measured by the weekly itch severity score [ISS7], 0-21 scale), the key secondary endpoint. Change from baseline in hives (measured by the weekly hive severity score [HSS7], 0-21 scale), secondary endpoint. Proportion of patients achieving well-controlled disease status (UAS7 ≤6). Proportion of patients with complete response (UAS7=0). About Dupixent Dupixent is an injection administered under the skin (subcutaneous injection) at different injection sites. In children aged 2 to 11 years with CSU who remain symptomatic despite H1AH treatment, Dupixent is administered based on age and weight. In children aged 2 to 5 years, Dupixent is administered at 200 mg every four weeks for patients weighing ≥5 kg to <15 kg and 300 mg every four weeks for ≥15 kg to <30 kg, without an initial loading dose. In children and adolescents aged 6 to 17 years, Dupixent is administered at 300 mg every four weeks for ≥15 kg to <30 kg,** 200 mg every two weeks for ≥30 kg to <60kg and 300mg every two weeks for ≥60 kg, after an initial loading dose. Dupixent is intended for use under the guidance of a healthcare professional and can be given in a clinic or at home after training by a healthcare professional. In children aged 2 to 11 years, Dupixent should be administered by a caregiver if given at home. Dupixent, which was invented using Regeneron’s proprietary VelocImmune ® technology, is a fully human monoclonal antibody that inhibits the signaling of the interleukin-4 (IL-4) and interleukin-13 (IL-13) pathways and is not an immunosuppressant. The Dupixent development program has shown significant clinical benefit and a decrease in type 2 inflammation in Phase 3 trials, establishing that IL-4 and IL-13 are two of the key and central drivers of the type 2 inflammation that plays a major role in multiple related and often co-morbid diseases. Dupixent has received regulatory approvals in more than 60 countries in one or more indications including certain patients with atopic dermatitis, asthma, chronic rhinosinusitis with nasal polyps (CRSwNP), eosinophilic esophagitis (EoE), prurigo nodularis, CSU, chronic obstructive pulmonary disease (COPD), bullous pemphigoid (BP) and allergic fungal rhinosinusitis (AFRS) in different age populations. More than 1,400,000 patients are being treated with Dupixent globally. 1 **For children and adolescents aged 6 to 17 years weighing 15 kg to <30 kg, the initial dose is 300 mg on Day 1 followed by 300 mg on Day 15. Subsequent doses are initiated four weeks after Day 15. 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, Board co-Chair, 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) and Veopoz ® (pozelimab-bbfg). In addition, REGEN-COV ® (casirivimab and imdevimab) had been authorized by the FDA during the COVID-19 pandemic until 2024. Dupilumab Development Program Dupilumab is being jointly developed by Regeneron and Sanofi under a global collaboration agreement. To date, dupilumab has been studied across more than 60 clinical trials involving more than 12,000 patients with various chronic diseases driven in part by type 2 inflammation. In addition to the currently approved indications, Regeneron and Sanofi are studying dupilumab in a broad range of diseases driven by type 2 inflammation or other allergic processes in Phase 3 trials, including chronic pruritus of unknown origin and lichen simplex chronicus. These potential uses of dupilumab are currently under clinical investigation, and the safety and efficacy in these conditions have not been fully evaluated by any regulatory authority. U.S. INDICATIONS DUPIXENT is a prescription medicine used: to treat adults and children 6 months of age and older with moderate-to-severe eczema (atopic dermatitis or AD) that is not well controlled with prescription therapies used on the skin (topical), or who cannot use topical therapies. DUPIXENT can be used with or without topical corticosteroids. It is not known if DUPIXENT is safe and effective in children with AD under 6 months of age. with other asthma medicines for the maintenance treatment of moderate-to-severe eosinophilic or oral steroid dependent asthma in adults and children 6 years of age and older whose asthma is not controlled with their current asthma medicines. DUPIXENT helps prevent severe asthma attacks (exacerbations) and can improve your breathing. DUPIXENT may also help reduce the amount of oral corticosteroids you need while preventing severe asthma attacks and improving your breathing. It is not known if DUPIXENT is safe and effective in children with asthma under 6 years of age. with other medicines for the maintenance treatment of chronic rhinosinusitis with nasal polyps (CRSwNP) in adults and children 12 years of age and older whose disease is not controlled. It is not known if DUPIXENT is safe and effective in children with CRSwNP under 12 years of age. to treat adults and children 1 year of age and older with eosinophilic esophagitis (EoE), who weigh at least 33 pounds (15 kg). It is not known if DUPIXENT is safe and effective in children with EoE under 1 year of age, or who weigh less than 33 pounds (15 kg). to treat adults with prurigo nodularis (PN). It is not known if DUPIXENT is safe and effective in children with PN under 18 years of age. with other medicines for the maintenance treatment of adults with inadequately controlled chronic obstructive pulmonary disease (COPD) and a high number of blood eosinophils (a type of white blood cell that may contribute to your COPD). DUPIXENT is used to reduce the number of flare-ups (the worsening of your COPD symptoms for several days) and can improve your breathing. It is not known if DUPIXENT is safe and effective in children with COPD under 18 years of age. to treat adults and children 12 years of age and older with chronic spontaneous urticaria (CSU) who continue to have hives that are not controlled with H1 antihistamine treatment. It is not known if DUPIXENT is safe and effective in children with CSU under 12 years of age, or who weigh less than 66 pounds (30 kg). to treat adults with bullous pemphigoid (BP). It is not known if DUPIXENT is safe and effective in children with BP under 18 years of age. to treat adults and children 6 years of age and older with allergic fungal rhinosinusitis (AFRS), who have had surgery on their nose or sinuses in the past. It is not known if DUPIXENT is safe and effective in children with AFRS under 6 years of age. DUPIXENT is not used to relieve sudden breathing problems and will not replace an inhaled rescue medicine or to treat any other forms of hives (urticaria). I M POR TA NT SAF E T Y I NF O RM ATIO N Do n o t u se if you are allergic to dupilumab or to any of the ingredients in DUPIXENT®. B e f o r e u s i n g D U P I X E N T , t e l l y ou r h ea l t h c a r e pr ov i de r a bou t a l l y ou r m edi c a l c o nd i t i on s , i nc l ud i n g i f y ou : have eye problems. have a parasitic (helminth) infection. are scheduled to receive any vaccinations. You should not receive a “live vaccine” right before and during treatment with DUPIXENT. are pregnant or plan to become pregnant. It is not known whether DUPIXENT will harm your unborn baby. A pregnancy registry for women who take DUPIXENT during pregnancy collects information about the health of you and your baby. are breastfeeding or plan to breastfeed. It is not known whether DUPIXENT passes into your breast milk. Tell your healthcare provider about all the medicines you take, including prescription and over-the-counter medicines, vitamins, and herbal supplements. Especially tell your healthcare provider if you are taking oral, topical, or inhaled corticosteroid medicines; have asthma and use an asthma medicine; or have AD, CRSwNP, EoE, PN, COPD, CSU, BP, or AFRS and also have asthma. Do not change or stop your other medicines, including corticosteroid medicine or other asthma medicine, without talking to your healthcare provider. This may cause other symptoms that were controlled by those medicines to come back. DUP I X E N T c a n c au se s e r i o u s si d e eff e c t s , i n cl ud i n g : All e r g i c r ea c t i on s. DUPIXENT can cause allergic reactions, including skin reactions, that can sometimes be severe. Stop using DUPIXENT and tell your healthcare provider or get emergency help right away if you get any of the following signs or symptoms: breathing problems or wheezing, swelling of the face, lips, mouth, tongue or throat, fainting, dizziness, feeling lightheaded, fast pulse, fever, hives, skin rash, including rash that looks like a bullseye, painful red or blue bumps under the skin, or red pus-filled spots on the skin, general ill feeling, itching, swollen lymph nodes, nausea or vomiting, joint pain, or cramps in your stomach area. E y e pr ob l e m s. Tell your healthcare provider if you have any new or worsening eye problems, including eye pain or changes in vision, such as blurred vision. Your healthcare provider may send you to an ophthalmologist for an exam if needed. I n fl a mm a t i o n o f y ou r b l oo d v e ss e l s. Rarely, this can happen in people with asthma who receive DUPIXENT. This may happen in people who also take a steroid medicine by mouth that is being stopped or the dose is being lowered. Tell your healthcare provider right away if you get: rash, chest pain, worsening shortness of breath, brown or dark colored urine, persistent fever, or a feeling of pins and needles or numbness of your arms or legs. Psoriasis . This can happen in people with atopic dermatitis and asthma who receive DUPIXENT. Tell your healthcare provider about any new skin symptoms. Your healthcare provider may send you to a dermatologist for an examination if needed. Joint aches and pain. Some people who use DUPIXENT have had trouble walking or moving due to their joint symptoms, and in some cases needed to be hospitalized. Tell your healthcare provider about any new or worsening joint symptoms. Your healthcare provider may stop DUPIXENT if you develop joint symptoms. T h e m o st c o m m o n s i d e effe c ts i nc l ude : Eczema: injection site reactions, eye problems, including eye and eyelid inflammation, redness, swelling, itching, eye infection, dry eye, and blurred vision, cold sores in your mouth or on your lips, and high count of a certain white blood cell (eosinophilia). A s t h ma: injection site reactions, high count of a certain white blood cell (eosinophilia), pain in the throat (oropharyngeal pain), and parasitic (helminth) infections. C h r on i c R h i no s i nu s i t i s w i th N a s a l P o ly p s: injection site reactions, eye problems, including eye and eyelid inflammation, redness, swelling, itching, eye infection, and blurred vision, high count of a certain white blood cell (eosinophilia), stomach problems (gastritis), joint pain (arthralgia), trouble sleeping (insomnia), and toothache. Eosinophilic Esophagitis: injection site reactions, upper respiratory tract infections, cold sores in your mouth or on your lips, and joint pain (arthralgia). Prurigo Nodularis: eye problems, including eye and eyelid inflammation, redness, swelling, itching, and blurred vision, herpes virus infections, common cold symptoms (nasopharyngitis), dizziness, muscle pain, and diarrhea. Chronic Obstructive Pulmonary Disease: injection site reactions, common cold symptoms (nasopharyngitis), high count of a certain white blood cell (eosinophilia), viral infection, back pain, inflammation inside the nose (rhinitis), diarrhea, stomach problems (gastritis), joint pain (arthralgia), toothache, headache, and urinary tract infection. Chronic Spontaneous Urticaria : injection site reactions. Bullous Pemphigoid : joint pain (arthralgia), eye problems, including eye and eyelid inflammation, redness, swelling, itching, and blurred vision, and herpes virus infections. Allergic Fungal Rhinosinusitis : injection site reactions, eye problems, including eye and eyelid inflammation, redness, swelling, itching, eye infection, and blurred vision, high count of a certain white blood cell (eosinophilia), stomach problems (gastritis), joint pain (arthralgia), trouble sleeping (insomnia), and toothache. Tell your healthcare provider if you have any side effect that bothers you or that does not go away. These are not all the possible side effects of DUPIXENT. Call your doctor for medical advice about side effects. You are encouraged to report negative side effects of prescription drugs to the FDA. Visit , or call 1-800-FDA-1088. Use DUPIXENT exactly as prescribed by your healthcare provider. It’s an injection given under the skin (subcutaneous injection). Your healthcare provider will decide if you or your caregiver can inject DUPIXENT. Do not try to prepare and inject DUPIXENT until you or your caregiver have been trained by your healthcare provider. In children 12 years of age and older, it’s recommended DUPIXENT be administered by or under supervision of an adult. In children 6 months to less than 12 years of age, DUPIXENT should be given by a caregiver. P l ea se s e e a cc o mp any i n g f u l l P r e s cri b i n g I n f o r ma t i o n i nc l ud i n g P a t i en t I n f o r ma t i o n. 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 . About Sanofi Sanofi is an R&D driven, AI-powered biopharma company committed to improving people’s lives and delivering compelling growth. We apply our deep understanding of the immune system to invent medicines and vaccines that treat and protect millions of people around the world, with an innovative pipeline that could benefit millions more. Our team is guided by one purpose: we chase the miracles of science to improve people’s lives; this inspires us to drive progress and deliver positive impact for our people and the communities we serve, by addressing the most urgent healthcare, environmental, and societal challenges of our time. Sanofi is listed on EURONEXT: SAN and NASDAQ: SNY. Regeneron 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 Dupixent ® (dupilumab) for the treatment of moderate-to-severe chronic spontaneous urticaria in children aged 2 years and above; 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 Dupixent for the treatment of chronic pruritus of unknown origin, lichen simplex chronicus, and other potential indications; uncertainty of the utilization, market acceptance, and commercial success of Regeneron’s Products (such as Dupixent) 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 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 Dupixent) 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; 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; 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. 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 ( ). Sanofi Disclaimers or Forward-Looking Statements This press release contains forward-looking statements within the meaning of applicable securities laws, including the Private Securities Litigation Reform Act of 1995, as amended. Forward-looking statements are statements that are not historical facts. These statements include projections and estimates and their underlying assumptions regarding the marketing and other potential of the product; regarding potential future events and revenues from the product. Words such as “expect,” “anticipate,” “believe,” “intend,” “estimate,” “plan,” “can,” “contemplate,” “could,” “is designed to,” “may,” “might,” “potential,” “objective,” "attempt," “target,” “project,” "strategy," "strive," "desire," “predict,” “forecast,” “ambition,” “guideline,” "seek," “should,” “will,” "goal," or the negative of these and similar expressions are intended to identify forward-looking statements. Although Sanofi’s management believes that the expectations reflected in such forward-looking statements are reasonable, investors are cautioned that forward-looking information and statements are subject to various risks and uncertainties, many of which are difficult to predict and generally beyond the control of Sanofi, that could cause actual results and developments to differ materially from those expressed in, or implied or projected by, the forward-looking information and statements. These risks, uncertainties and assumptions include among other things, unexpected regulatory actions or delays, or government regulation generally, that could affect the availability or commercial potential of the product, the fact that product may not be commercially successful; authorities’ decisions regarding whether and when to approve a product candidate; political pressure in the United States to mandate lower drug prices including “most favored nation” pricing for State Medicaid programs; the uncertainties inherent in research and development, including future clinical data and analysis of existing clinical data relating to the product, including post marketing, unexpected safety, quality or manufacturing issues; competition in general; risks associated with intellectual property and any related pending or future litigation and the ultimate outcome of such litigation, and volatile economic and market conditions, and the impact that global crises may have on us, our customers, suppliers, vendors, and other business partners, and the financial condition of any one of them, as well as on our employees and on the global economy as a whole. The risks and uncertainties also include the uncertainties discussed or identified in the public filings with the SEC and the French Markets Authority (AMF) made by Sanofi, including those listed under “Risk Factors” and “Cautionary Statement Regarding Forward-Looking Statements” in Sanofi’s annual report on Form 20-F for the year ended December 31, 2025 or contained in our periodic reports on Form 6-K. Other than as required by applicable law, Sanofi does not undertake any obligation to update or revise any forward-looking information or statements. In light of these risks, uncertainties and assumptions, you should not place undue reliance on any forward-looking statements contained herein. All trademarks mentioned in this press release are the property of the Sanofi group except for VelociSuite and Regeneron Genetics Center. Regeneron Contacts: Media Relations Investor Relations Kailey Kilmartin Tel: +1 914-652-0679 Kailey.Kilmartin@regeneron.com Mark Hudson Tel: +1 914-847-3482 Mark.Hudson@regeneron.com Sanofi Contacts: Media Relations Investor Relations Sandrine Guendoul Tel: +33 6 25 09 14 25 Sandrine.Guendoul@sanofi.com Thomas Kudsk Larsen Tel: +44 7545 513 693 Thomas.Larsen@sanofi.com Evan Berland Tel: +1 215-432-0234 Evan.Berland@sanofi.com Alizé Kaisserian Tel: +33 6 47 04 12 11 Alize.Kaisserian@sanofi.com L éo Le Bourhis Tel: + 33 6 75 06 43 81 leo.lebourhis@sanofi.com Keita Browne Tel: +1 781-249-1766 Keita.Browne@sanofi.com Victor Rouault Tel: +1 617-356-4751 Victor.Rouault@sanofi.com Nathalie Pham Tel: +33 7 85 93 30 17 Nathalie.Pham@sanofi.com Timothy Gilbert Tel: +1 516-521-2929 Timothy.Gilbert@sanofi.com Nina Goworek Tel: +1 908 569 7086 Nina.Goworek@sanofi.com L éa Ubaldi Tel: + 33 6 30 19 66 46 lea.ubaldi@sanofi.com Thibaud Châtelet Tel: +33 6 80 80 89 90 Thibaud.Chatelet@sanofi.com Ekaterina Pesheva Tel: +1 410 926 6780 ekaterina.pesheva@sanofi.com Yun Li Tel: +33 6 84 00 90 72 Yun.Li3@sanofi.com 1 Data on File