Regeneron Pharmaceuticals, Inc.?(NASDAQ: REGN) and Sanofi today announced that the?U.S. Food and Drug Administration?(FDA) has accepted for review the supplemental Biologics License Application (sBLA) for Dupixent^??(dupilumab) as an add-on treatment for children aged 6 to 11 years with uncontrolled moderate-to-severe asthma. Dupixent is currently approved as an add-on treatment for patients with uncontrolled moderate-to-severe asthma aged 12 and older with elevated eosinophils or oral corticosteroid dependent asthma. The target action date for the FDA decision is?October 21, 2021?and the?European Union?(EU) regulatory submission for children aged 6 to 11 years with asthma is planned for Q1 2021. In the?U.S., there are approximately 75,000 children aged 6 to 11 years with uncontrolled moderate-to-severe asthma, which can carry a significant burden for children and their families. Despite treatment with current standard-of-care inhaled corticosteroids and bronchodilators, these children can still experience coughing, wheezing, and difficulty breathing. They are also at risk for life-threatening severe asthma attacks that can lead to hospitalization and emergency room visits, and may require the use of systemic corticosteroids which carry significant risks when used long term. Uncontrolled moderate-to-severe asthma can impair lung function, and can interfere with day-to-day activities, like sleeping, attending school and playing sports. The sBLA is supported by data that include pivotal?Phase 3 results?evaluating the efficacy and safety of Dupixent in addition to standard-of-care maintenance therapy in children with moderate-to-severe asthma with type 2 inflammation, characterized by raised blood eosinophil levels and/or raised fractional exhaled nitric oxide (FeNO) levels. In the trial, Dupixent significantly reduced severe asthma attacks and rapidly improved lung function within two weeks in children aged 6 to 11 years. Safety results were generally consistent with the well-established safety profile of Dupixent in the approved indication for patients aged 12 and older with moderate-to-severe asthma. Adverse events in the Phase 3 trial that were more commonly observed with Dupixent included injection site reactions, viral upper respiratory tract infections and eosinophilia. Detailed results from this Phase 3 trial will be published later this year. Dupixent 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. It was invented using Regeneron's proprietary?VelocImmune^??technology. IL-4 and IL-13 are key and central drivers of the type 2 inflammation that plays a major role in asthma, chronic rhinosinusitis with nasal polyposis (CRSwNP), atopic dermatitis and eosinophilic esophagitis. About Dupixent Dupixent is approved in the?U.S.?to treat patients aged 6 years and older with moderate-to-severe atopic dermatitis that is not well controlled with prescription therapies used on the skin (topical), or who cannot use topical therapies; for use with other asthma medicines for the maintenance treatment of moderate-to-severe eosinophilic or oral steroid dependent asthma in patients aged 12 years and older whose asthma is not controlled with their current asthma medicines; and for use with other medicines for the maintenance treatment of CRSwNP in adults whose disease is not controlled. Outside of the?U.S., Dupixent is approved for specific patients with moderate-to-severe atopic dermatitis and certain patients with asthma in a number of other countries around the world, including those in the EU and?Japan. Dupixent is also approved in the EU and?Japan?to treat certain adults with severe CRSwNP. Across all approved indications globally, more than 200,000 patients have been treated with Dupixent. Dupixent is intended for use under the guidance of a healthcare professional and can be given in a clinic or at home by self-administration after training by a healthcare professional. In children younger than 12 years of age, Dupixent should be administered by a caregiver. About Regeneron's?VelocImmune^??Technology Dupixent was invented using Regeneron's?VelocImmune?technology that 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 multiple antibodies including Libtayo^??(cemiplimab-rwlc), Praluent^??(alirocumab), Kevzara^??(sarilumab), Evkeeza^??(evinacumab-dgnb), Inmazeb^??(atoltivimab, maftivimab, and odesivimab-ebgn). Dupilumab Development Program To date, dupilumab has been studied in more than 10,000 patients across 50 clinical trials in various chronic diseases driven 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, including pediatric asthma (6 to 11 years of age, Phase 3), chronic obstructive pulmonary disease with evidence of type 2 inflammation (Phase 3), pediatric atopic dermatitis (6 months to 5 years of age, Phase 3), eosinophilic esophagitis (Phase 3), bullous pemphigoid (Phase 3), prurigo nodularis (Phase 3), chronic spontaneous urticaria (Phase 3), chronic inducible urticaria-cold (Phase 3), chronic rhinosinusitis without nasal polyposis (Phase 3), allergic fungal rhinosinusitis (Phase 3) and food allergies (Phase 2). These potential uses are under clinical investigation, and the safety and efficacy of dupilumab in these conditions have not been fully evaluated by any regulatory authority. Dupilumab is being jointly developed by Regeneron and Sanofi under a global collaboration agreement. U.S.?INDICATIONS DUPIXENT?is a?prescription?medicine?used:

• to treat people aged 6 years and older with moderate-to-severe atopic dermatitis (eczema) 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 atopic dermatitis under 6 years of age.
• with other asthma medicines for the maintenance treatment of moderate-to-severe eosinophilic or oral steroid dependent asthma in people aged 12 years 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. DUPIXENT is not used to treat sudden breathing problems. It is not known if DUPIXENT is safe and effective in children with asthma under 12 years of age.
• with other medicines for the maintenance treatment of chronic rhinosinusitis with nasal polyposis (CRSwNP) in adults whose disease is not controlled. It is not known if DUPIXENT is safe and effective in children with chronic rhinosinusitis with nasal polyposis under 18 years of age.

IMPORTANT?SAFETY?INFORMATION FOR?U.S.?PATIENTS Do?not?use?if you?are?allergic?to?dupilumab?or?to?any?of the?ingredients?in?DUPIXENT^?. Before using?DUPIXENT,?tell?your?healthcare?provider?about?all?your?medical?conditions,?including?if you:

• have eye problems
• have a parasitic (helminth) infection
• are scheduled to receive any vaccinations. You should not receive a "live vaccine" if you are treated with DUPIXENT.
• are pregnant or plan to become pregnant. It is not known whether DUPIXENT will harm your unborn baby.
• o There is a pregnancy exposure registry for women who take DUPIXENT during pregnancy to collect information about the health of you and your baby. Your healthcare provider can enroll you or you may enroll yourself. To get more information about the registry call 1?877-311-8972 or go to?https://mothertobaby.org/ongoing-study/dupixent/.
• 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 atopic dermatitis or CRSwNP, and also have asthma.?Do not?change or stop your corticosteroid medicine or other asthma medicine without talking to your healthcare provider. This may cause other symptoms that were controlled by the corticosteroid medicine or other asthma medicine to come back. DUPIXENT?can?cause?serious?side?effects,?including:

• Allergic reactions (hypersensitivity), including a severe reaction known as anaphylaxis.?Stop using DUPIXENT and tell your healthcare provider or get emergency help right away if you get any of the following symptoms: breathing problems, fever, general ill feeling, swollen lymph nodes, swelling of the face, mouth and tongue, hives, itching, fainting, dizziness, feeling lightheaded (low blood pressure), joint pain, or skin rash.
• Eye problems. Tell your healthcare provider if you have any new or worsening eye problems, including eye pain or changes in vision.
• Inflammation of your blood vessels. 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. It is not known whether this is caused by DUPIXENT. Tell your healthcare provider right away if you have: rash, shortness of breath, persistent fever, chest pain, or a feeling of pins and needles or numbness of your arms or legs.

The most common side effects by indication are as follows:

• Atopic dermatitis:?injection site reactions, eye and eyelid inflammation, including redness, swelling, and itching, and cold sores in your mouth or on your lips.
• Asthma:?injection site reactions, pain in the throat (oropharyngeal pain), and high count of a certain white blood cell (eosinophilia).
• Chronic rhinosinusitis with nasal polyposis:?injection site reactions, eye and eyelid inflammation, including redness, swelling, and itching, high count of a certain white blood cell (eosinophilia), trouble sleeping (insomnia), toothache, gastritis, and joint pain (arthralgia).

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?www.fda.gov/medwatch,?or call 1-800-FDA-1088. Use?DUPIXENT?exactly?as prescribed. Your healthcare provider will tell you how much DUPIXENT to inject and how often to inject it. DUPIXENT?is an injection?given under?the?skin?(subcutaneous injection).?If your healthcare?provider?decides?that?you?or?a?caregiver?can?give?DUPIXENT?injections,?you or your?caregiver?should?receive?training?on?the?right?way?to?prepare?and?inject?DUPIXENT.?Do?not?try?to inject?DUPIXENT?until?you?have?been shown the?right?way?by?your healthcare?provider.?In?children?12 years?of age?and?older,?it?is?recommended?that?DUPIXENT?be?administered by?or under?supervision?of an adult. In children younger than 12 years of age, DUPIXENT should be given by a caregiver. Please?see?accompanying?full?Prescribing?Information?including?Patient?Information. About Regeneron Regeneron?(NASDAQ: REGN) is a leading biotechnology company that invents life-transforming medicines for people with serious diseases. Founded and led for over 30 years by physician-scientists, our unique ability to repeatedly and consistently translate science into medicine has led to nine FDA-approved treatments and numerous product candidates in development, almost all 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, pain, infectious diseases and rare diseases. Regeneron is accelerating and improving the traditional drug development process through our proprietary?VelociSuite^??technologies, such as?VelocImmune,?which uses unique genetically humanized mice to produce optimized fully human antibodies and bispecific antibodies, and through ambitious research initiatives such as the Regeneron Genetics Center, which is conducting one of the largest genetics sequencing efforts in the world. For additional information about the company, please visit?www.regeneron.com?or follow @Regeneron on Twitter. About Sanofi Sanofi?is dedicated to supporting people through their health challenges. We are a global biopharmaceutical company focused on human health. We prevent illness with vaccines, provide innovative treatments to fight pain and ease suffering. We stand by the few who suffer from rare diseases and the millions with long-term chronic conditions. With more than 100,000 people in 100 countries,?Sanofi?is transforming scientific innovation into healthcare solutions around the globe. Sanofi, Empowering Life 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 impact of SARS-CoV-2 (the virus that has caused the COVID-19 pandemic) on Regeneron's business and its employees, collaborators, and suppliers and other third parties on which Regeneron relies, Regeneron's and its collaborators' ability to continue to conduct research and clinical programs, Regeneron's ability to manage its supply chain, net product sales of products marketed or otherwise commercialized by Regeneron and/or its collaborators (collectively, "Regeneron's Products"), and the global economy; the nature, timing, and possible success and therapeutic applications of Regeneron's Products and product candidates being developed by Regeneron and/or its collaborators (collectively, "Regeneron's Product Candidates") and research and clinical programs now underway or planned, including without limitation Dupixent^??(dupilumab) as an add-on treatment for children aged 6 to 11 years with uncontrolled moderate-to-severe asthma characterized by raised blood eosinophil levels and/or raised fractional exhaled nitric oxide (FeNO) levels ("Pediatric Asthma"); 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?dupilumab for the treatment of Pediatric Asthma, chronic obstructive pulmonary disease, pediatric atopic dermatitis, eosinophilic esophagitis, bullous pemphigoid, prurigo nodularis, chronic spontaneous urticaria, food and environmental allergies, and other potential indications; uncertainty of 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 the commercial success of Regeneron's Products and?Regeneron's Product Candidates; safety issues resulting from the administration of Regeneron's Products and?Regeneron's Product Candidates?in patients, including serious complications or side effects in connection?with the use of Regeneron's Products and Regeneron's Product Candidates in clinical trials; 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 of Regeneron's Products from third-party payers, including private payer 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 payers and new policies and procedures adopted by such payers; competing drugs and product candidates 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 may be replicated in other studies and/or?lead to advancement of product candidates to clinical trials, therapeutic applications, or regulatory approval; the ability of Regeneron to manufacture and manage supply chains for multiple products and product candidates; the ability of Regeneron's collaborators, suppliers, or other third parties (as applicable) to perform manufacturing, filling, finishing, packaging, labeling, distribution, and other steps related to Regeneron's Products and Regeneron's Product Candidates; 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, Bayer, and Teva Pharmaceutical Industries Ltd. (or their respective affiliated companies, as applicable), to be cancelled or terminated; and 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, Dupixent,?Praluent^??(alirocumab), and REGEN-COV^??(casirivimab and imdevimab)), other litigation and other proceedings and government investigations relating to the Company and/or its operations, 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, 2020.? 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 (http://newsroom.regeneron.com) and its Twitter feed (http://twitter.com/regeneron). 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These risks and uncertainties 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, 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 future litigation and the ultimate outcome of such litigation, and volatile economic and market conditions, and the impact that COVID-19 will 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.? Any material effect of COVID-19 on any of the foregoing could also adversely impact us. This situation is changing rapidly and additional impacts may arise of which we are not currently aware and may exacerbate other previously identified risks. The risks and uncertainties also include the uncertainties discussed or identified in the public filings with the?SEC?and the 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, 2019. Other than as required by applicable law, Sanofi does not undertake any obligation to update or revise any forward-looking information or statements.