Regeneron Pharmaceuticals, Inc.?(NASDAQ: REGN) and Sanofi today announced that detailed results from a Phase 3 trial showed Dupixent^??(dupilumab) significantly reduced severe asthma attacks, and within two weeks rapidly improved lung function in children aged 6 to 11 years with uncontrolled moderate-to-severe asthma, with evidence of type 2 inflammation. Dupixent also significantly improved overall asthma symptom control and reduced an airway biomarker of type 2 inflammation that plays a major role in asthma, called fractional exhaled nitric oxide (FeNO). These data are being presented at the 2021?American Thoracic Society International Conference?(ATS 2021) and featured in the?Breaking News: Clinical Trial Results in Pulmonary Medicine?Scientific Symposium. "Children living with uncontrolled moderate-to-severe asthma experience serious and persistent symptoms that can impact many crucial aspects of their lives including school, sleep and exercise," said?Leonard B. Bacharier, M.D., Professor of Pediatrics and Director of the?Center for Pediatric Asthma Research,?Monroe Carell Jr. Children's Hospital?at?Vanderbilt University Medical Center?in?Nashville, Tennessee?and principal investigator of the trial. "The trial results show that dupilumab, when added to standard-of-care therapy, significantly reduced asthma attacks, rapidly improved lung function and improved asthma control, which is especially important to these children during a particularly formative time in their lives." Asthma is the most common chronic disease in children, with approximately 75,000 children aged 6 to 11 years living with the uncontrolled moderate-to-severe form of the disease in the?U.S., and many more worldwide. Despite treatment with current standard-of-care inhaled corticosteroids and bronchodilators, these children may continue to experience serious symptoms such as coughing, wheezing and difficulty breathing. They also may require the use of multiple courses of systemic corticosteroids that carry significant risks. Children who have asthma with underlying type 2 inflammation, which is the most common cause of asthma in children, are more likely to have poor asthma control, more frequent asthma attacks and symptoms that interfere with day-to-day activities. The Phase 3, randomized, double-blind, placebo-controlled VOYAGE trial evaluated the efficacy and safety of Dupixent (100 mg or 200 mg every two weeks, based on weight) combined with standard-of-care asthma therapy?in 408 children with uncontrolled moderate-to-severe asthma. Two pre-specified populations with evidence of type 2 inflammation were evaluated for the primary analysis: 1) patients with baseline blood eosinophils (EOS) =300 cells/?l (n=259) and 2) patients with FeNO =20 parts per billion (ppb) or EOS =150 cells/?l (n=350). Top line results from the trial, which met its primary and key secondary endpoints, were?announced?in?October 2020. These data showed that patients who added Dupixent to standard-of-care in these two patient groups, respectively, experienced:

• Substantially reduced rate of severe asthma attacks, with a 65% (p<0.0001) and 59% (p<0.0001) average reduction over one year compared to placebo (0.24 and 0.31 events per year for Dupixent vs. 0.67 and 0.75 for placebo, respectively).
• Improved lung function observed as early as two weeks and sustained for up to 52 weeks, measured by percent predicted FEV₁?(FEV₁pp).
  • At 12 weeks, patients taking Dupixent improved their lung function by 5.32 and 5.21 percentage points vs. placebo (p=0.0036 and p=0.0009, respectively).
  • This measure seeks to evaluate a patient's change in lung function compared to their predicted lung function based on age, height, sex and ethnicity to account for children's growing lung capacity at different stages of development.

New VOYAGE Data Presented at ATS Results presented for the first time at ATS in the primary patient populations showed patients taking Dupixent experienced:

• Significant improvement in asthma control at week 24 based on patient-reported disease symptoms and impact, measured on a 0-6 scale. On average, patients taking Dupixent improved their scores by 1.34 and 1.33 from baseline compared to 0.88 and 1.00 for placebo (average improvement of ?0.46 and -0.33 for Dupixent vs. placebo, p<0.0001 and p=0.0001, respectively). The improvement from baseline in patients taking Dupixent was more than double the clinically meaningful threshold of 0.5 points on the Asthma Control Questionnaire 7-Interviewer Administered (ACQ-7-IA).
• Significant reduction in mean?FeNO levels to below the threshold for type 2 inflammation, which is 20 parts per billion (ppb). Patients taking Dupixent had an average improvement in FeNO levels by -20.59 and -17.84 ppb vs. placebo from baseline to week 12 (p<0.0001 for both values).

The safety results from the trial were generally consistent with the known safety profile of Dupixent in patients aged 12 years and older with uncontrolled moderate-to-severe asthma. The overall rates of adverse events were 83% for Dupixent and 80% for placebo. Adverse events that were most commonly observed with Dupixent versus placebo included injection site reactions (18% Dupixent, 13% placebo), viral upper respiratory tract infections (12% Dupixent, 10% placebo) and eosinophilia (6% Dupixent, 1% placebo). The safety and efficacy of Dupixent in this pediatric population have not been fully evaluated by any regulatory authority. 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 260,000 patients have been treated with Dupixent. 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 multiple antibodies including Dupixent, Libtayo^??(cemiplimab-rwlc), Praluent^??(alirocumab), Kevzara^??(sarilumab), Evkeeza^??(evinacumab-dgnb) and Inmazeb^TM?(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), allergic bronchopulmonary aspergillosis (Phase 3) and food allergies (Phase 2). 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. 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.
  • 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) for the treatment of children aged 6 to 11 years with uncontrolled moderate-to-severe 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?Dupixent for the treatment of pediatric asthma, chronic obstructive pulmonary disease with evidence of type 2 inflammation, pediatric atopic dermatitis, eosinophilic esophagitis, bullous pemphigoid, prurigo nodularis, chronic spontaneous urticaria, chronic inducible urticaria-cold, chronic rhinosinusitis without nasal polyposis, allergic fungal rhinosinusitis, food allergies, and other potential indications; 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 study discussed in this press release, on any of the foregoing or any potential regulatory approval of Regeneron's Products and Regeneron's 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; the ability of Regeneron to manage supply chains for multiple products and product candidates; 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, including without limitation Dupixent; 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; 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^TM?(casirivimab with 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?and its Form 10-Q for the quarterly period ended?March 31, 2021. 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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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.