PARIS and TARRYTOWN, N.Y. ? March 30, 2020 ? The first patient outside of the U.S. has been treated as part of a global clinical program evaluating Kevzara? (sarilumab) in patients hospitalized with severe COVID-19. The global clinical program has now been initiated in Italy, Spain, Germany, France, Canada, Russia and the United States ? all countries that have been impacted by COVID-19. This is the second multi-center, double-blind, Phase 2/3 trial as part of the Kevzara COVID-19 program, and the companies are continuing to work with health authorities around the world to secure initiation at additional sites. This follows Sanofi and Regeneron?s announcement earlier this month of the initiation of the first trial, which is U.S.-based. ?Sanofi and Regeneron are relentlessly working to rapidly initiate trials around the world that will help determine whether Kevzara has the potential to play a role in addressing the COVID-19 global health crisis. These trials will provide important data to determine whether Kevzara ameliorates the life-threatening complications of COVID-19 infections by counteracting the overactive inflammatory responses in the lungs when damaged by the virus. In these unprecedented times, we are deeply grateful for the daily collaboration with health authorities that are enabling us to conduct this clinical work so quickly,? said John Reed, M.D., Ph.D., Sanofi?s Global Head of Research and Development. ?In addition to this clinical trial aiming to help critically ill COVID-19 patients, our work continues to bring forth a vaccine for disease prevention, along with efforts to provide other important Sanofi medicines that may help patients impacted by COVID-19.? Kevzara is a fully-human monoclonal antibody that inhibits the interleukin-6 (IL-6) pathway by binding and blocking the IL-6 receptor. IL-6 may play a role in driving the overactive inflammatory response in the lungs of patients who are severely or critically ill with COVID-19 infection. The role of IL-6 is supported by preliminary data from a single-arm study in China using another IL-6 receptor inhibitor. ?Data from a single-arm study in China suggest that the interleukin-6 pathway may play an important role in the overactive inflammatory response in the lungs of patients with COVID-19. Despite this encouraging finding, it's imperative to conduct a properly designed, randomized trial to understand the true impact of Kevzara, which we are now doing through this global clinical trial program,? said George D. Yancopoulos, M.D., Ph.D., Co-founder, President and Chief Scientific Officer of Regeneron. ?In addition to the Kevzara program, Regeneron continues to rapidly advance a novel antibody cocktail for the prevention and treatment of COVID-19.? The trial outside of the U.S. will assess the safety and efficacy of adding a single intravenous dose of Kevzara to usual supportive care, compared to supportive care plus placebo. The trial has an adaptive design with two parts and is anticipated to enroll approximately 300 patients. The trial will recruit hospitalized patients from several countries who are severely or critically ill with COVID-19 infection. Scientists have preliminary evidence that IL-6 may play a key role in driving the inflammatory immune response that causes acute respiratory distress syndrome (ARDS) in patients critically ill from COVID-19. In an initial, non-peer-reviewed case series from China, a 21-patient cohort of COVID-19 patients experienced rapidly reduced fevers and 75% of patients (15 out of 20) reduced their need for supplemental oxygen within days of receiving another IL-6 receptor antibody (tocilizumab). Based on these results, China updated its COVID-19 treatment guidelines and approved the use of that IL-6 inhibitor to treat patients with severe or critical disease. The use of Kevzara to treat the symptoms of COVID-19 is investigational and has not been evaluated by any regulatory authority. About the Trial This Phase 2/3, randomized, double-blind, placebo-controlled trial uses an adaptive design to evaluate the safety and efficacy of Kevzara in adults hospitalized with serious complications from COVID-19. To enter the trial, patients must have pneumonia and be hospitalized with laboratory-confirmed COVID-19 that is classified as severe or critical, or who are suffering from multi-organ dysfunction. After receiving the study dose, patients will be assessed for 60 days, or until hospital discharge or death. In the Phase 2 part of the trial, patients will be randomized 2:2:1 into three groups: Kevzara higher dose, Kevzara lower dose and placebo. The Phase 2 findings will be utilized in an adaptive manner to determine transition into Phase 3, helping to determine the endpoints, patient numbers and doses. If the trial continues with all three treatment arms to the end, it is expected to enroll approximately 300 patients, depending on the status of the COVID-19 outbreak and the proportion of patients with severe COVID-19. About Kevzara? (sarilumab) Injection Kevzara is currently approved in multiple countries to treat adults with moderately to severely active rheumatoid arthritis who have not responded to or tolerated previous therapy. Kevzara was jointly developed by Sanofi and Regeneron under a global collaboration agreement. Kevzara is a fully-human monoclonal antibody. Kevzara binds specifically to the IL-6 receptor, and has been shown to inhibit IL-6-mediated signaling. IL-6 is an immune system protein produced in increased quantities in patients with rheumatoid arthritis and has been associated with disease activity, joint destruction and other systemic problems. Kevzara is being investigated for its ability to reduce the overactive inflammatory immune response associated with COVID-19 based on evidence of markedly elevated levels of IL-6 in severely ill patients infected with coronaviruses. IMPORTANT SAFETY INFORMATION FOR KEVZARA? (sarilumab) INJECTION KEVZARA can cause serious side effects including: SERIOUS INFECTIONS: KEVZARA is a medicine that affects your immune system. KEVZARA can lower the ability of your immune system to fight infections. Some people have serious infections while using KEVZARA, including tuberculosis (TB), and infections caused by bacteria, fungi, or viruses that can spread throughout the body. Some people have died from these infections. Your healthcare provider should test you for TB before starting KEVZARA. Your healthcare provider should monitor you closely for signs and symptoms of TB during treatment with KEVZARA.

• Before starting KEVZARA, tell your healthcare provider if you:
  • think you have an infection or have symptoms of an infection, with or without a fever. Symptoms may include sweats or chills, muscle aches, a cough, shortness of breath, blood in your phlegm, weight loss, warm, red, or painful skin or sores on your body, diarrhea or stomach pain, burning when you urinate or urinating more often than normal, if you feel very tired, or if you are being treated for an infection, get a lot of infections or have repeated infections
  • have diabetes, HIV, or a weakened immune system
  • have TB, or have been in close contact with someone with TB
  • live or have lived, or have traveled to certain parts of the country (such as the Ohio and Mississippi River valleys and the Southwest) where there is an increased chance of getting certain fungal infections (histoplasmosis, coccidioidomycosis, or blastomycosis)
  • have or have had hepatitis
• After starting KEVZARA, call your healthcare provider right away if you have any symptoms of an infection.

• • CHANGES IN CERTAIN LABORATORY TEST RESULTS: Your healthcare provider should do blood tests before and after starting KEVZARA to check for low neutrophil (white blood cells that help the body fight off bacterial infections) counts, low platelet (blood cells that help with blood clotting and stop bleeding) counts, and an increase in certain liver function tests. Changes in test results are common with KEVZARA and can be severe. You may also have changes in other laboratory tests, such as your blood cholesterol levels. Your healthcare provider should do blood tests 4 to 8 weeks after starting KEVZARA and then every 6 months during treatment to check for an increase in blood cholesterol levels.
    • TEARS (PERFORATION) OF THE STOMACH OR INTESTINES:?Tell your healthcare provider if you have had a condition known as diverticulitis (inflammation in parts of the large intestine) or ulcers in your stomach or intestines. Some people using KEVZARA had tears in their stomach or intestine. This happens most often in people who also take nonsteroidal anti-inflammatory drugs (NSAIDS), corticosteroids, or methotrexate. Call your healthcare provider right away if you have fever and stomach (abdominal) pain that does not go away.
    • CANCER: KEVZARA may increase your risk of certain cancers by changing the way your immune system works. Tell your healthcare provider if you have ever had any type of cancer.
    • SERIOUS ALLERGIC REACTIONS:?Serious allergic reactions can happen with KEVZARA. Get medical attention right away if you have any of the following signs: shortness of breath or trouble breathing; feeling dizzy or faint; swelling of your lips, tongue or face; moderate or severe stomach (abdominal) pain or vomiting; or chest pain.
    • Do not use KEVZARA if you are allergic to Sarilumab or any of the ingredients of KEVZARA.
    • Before using KEVZARA, tell your healthcare provider if you
      • have an infection
      • have liver problems
      • have had stomach (abdominal) pain or a condition known as diverticulitis (inflammation in parts of the large intestine) or ulcers in your stomach or intestines
      • recently received or are scheduled to receive a vaccine. People who take KEVZARA should not receive live vaccines
      • plan to have surgery or a medical procedure
      • are pregnant or plan to become pregnant. It is not known if KEVZARA will harm your unborn baby
      • are breastfeeding or plan to breastfeed. Talk to your healthcare provider about the best way to feed your baby if you use KEVZARA. It is not known if KEVZARA passes into your breast milk
      • take any prescription or nonprescription medicines, vitamins or herbal supplements. It is especially important to tell your healthcare provider if you use any other medicines to treat your RA. Using KEVZARA with these medicines may increase your risk of infection
      • medicines that affect the way certain liver enzymes work. Ask your healthcare provider if you are not sure if your medicine is one of these
    • The most common side effects include:
      • injection site redness
      • upper respiratory tract infection
      • urinary tract infection
      • nasal congestion, sore throat, and runny nose

These are not all the possible side effects of KEVZARA. Tell your doctor about any side effect that bothers you or does not go away. You are encouraged to report side effects of prescription drugs to the FDA at www.fda.gov/medwatch or call 1-800-FDA-1088. WHAT IS KEVZARA? KEVZARA is an injectable prescription medicine called an interleukin-6 (IL-6) receptor blocker. KEVZARA is used to treat adult patients with moderately to severely active rheumatoid arthritis (RA) after at least one other medicine called a disease-modifying antirheumatic drug (DMARD) has been used and did not work well or could not be tolerated. To learn more, talk about KEVZARA with your healthcare provider or pharmacist. The FDA-approved Medication Guide and Prescribing Information can be found below, or by calling 1-844-KEVZARA (1-844-538-92721-844-538-9272). Click here for full Prescribing Information including risk of SERIOUS SIDE EFFECTS and Medication Guide for KEVZARA. 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 seven FDA-approved treatments and numerous product candidates in development, 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

Media Relations Contact for Sanofi Ashleigh Koss Tel.: +1 908-981-8745 Ashleigh.Koss@sanofi.com	Investor Relations Contact for Sanofi Felix Lauscher Tel.: +33 (0)1 53 77 45 45 ir@sanofi.com
Media Relations Contact for Regeneron? Sarah Cornhill Tel: +1 (914) 847-5018 Sarah.cornhill@regeneron.com	Investor Relations Contact for Regeneron Justin Holko Tel: +1 (914) 847-7786 Justin.Holko@regeneron.com

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