GlobeNewswire Inc | May 27, 2021 01:30AM EDT

May 27, 2021

Sanofi and GSK initiateglobal Phase 3clinical efficacy study of COVID-19 vaccinecandidate

-- Two-stage design will evaluate vaccine formulations targeting original D.614 virus as well as B.1.351 variant, in diverse geographies with multiple circulating variants -- A booster study program will begin in the coming weeks to complement Phase 3 trial -- Pending positive Phase 3 outcomes and regulatory reviews, the vaccine could be approved in Q4 2021

PARIS and LONDON May 27, 2021 Today, Sanofi and GSK started enrollment in their Phase 3 clinical study to assess the safety, efficacy, and immunogenicity oftheir adjuvanted recombinant-protein COVID-19 vaccine candidate. The global, randomized, double-blind placebo-controlled Phase 3 study will include more than 35,000 volunteersaged 18 and olderfrom several countries, including sites in the US, Asia, Africa, and Latin America.

The primary endpoint of the study is the prevention of symptomatic COVID-19 in SARS-CoV-2 nave adults, with secondary endpoints being the prevention of severe COVID-19 disease and prevention of asymptomatic infection. In a two-stage approach, the study will initially investigate the efficacy of a vaccine formulation targeting the original D.614 virus (Wuhan), while a second stage will evaluate a second formulation targeting the B.1.351 (South African) variant. Recent scientific evidence1 shows that antibodies created against the B.1.351 variant may provide broad cross-protection against other more transmissible variants. The design of the Phase 3, conducted across a broad diversity of geographies, also allows evaluation of the efficacy of the candidate against a variety of circulating variants.

Following encouraging interim results from the recent Phase 2 study, the companies will also begin clinical studies in the coming weeks to assess the ability of the adjuvanted recombinant-protein COVID-19 vaccine candidate to generate a strong booster response regardless of initial vaccine platform received.

We are encouraged to see first vaccinations starting to take place in such an important, pivotal Phase 3 study, aswe believe that our unique technology platform will provide a clinically-relevant vaccine option said Thomas Triomphe, Executive Vice President, Global Head of Sanofi Pasteur. We have adapted our vaccine development strategy based on forward-looking considerations as the virus continues to evolve, as well as anticipating what may be needed in a post-pandemic setting. This trial is testament totheurgency and agility in our approach to help overcome the ongoing impact of this pandemic.

Roger Connor, President of GSK Vaccines added, We believe further solutions for COVID-19 are very much needed to help reach people around the world, especially as the pandemic evolves and variants continue to emerge. Adjusting our technology and study designs reflects this need and will further build the potential of this adjuvanted protein-based vaccine. We are grateful to the volunteers who will take part in the trials and hope the results will addtothe encouraging data weve seen so far so we can make the vaccine available as quickly as possible.

The Phase 3 study follows the interim Phase 2 results which showed that the adjuvanted recombinant COVID-19 vaccine candidate achieved high rates of neutralizing antibody responses in all adult age groups, with 95 to 100% seroconversion rates. After a single injection, high neutralizing antibody levels were also generated in participants with evidence of prior SARS-CoV-2 infection, suggesting strong potential for development as a booster vaccine.

Pending positive Phase 3 outcomes and regulatory reviews, the vaccine could be approved / authorized in Q4 2021. Manufacturing will begin in the coming weeks to enable rapid access to the vaccine should it be approved.

This effort is supported by federal funds from the Biomedical Advanced Research and Development Authority, part of the office of the Assistant Secretary for Preparedness and Response at the U.S. Department of Health and Human Services in collaboration with the U.S. Department of Defense Joint Program Executive Office for Chemical, Biological, Radiological and Nuclear Defense under Contract # W15QKN-16-9-1002.

About the Sanofi and GSK partnershipIn the partnership between the two Companies, Sanofi provides its recombinant antigen and GSK contributes its pandemic adjuvant, both established vaccine platforms that have proven successful against influenza. The recombinant technology combined with GSKs adjuvant is designed to offer the advantages of stability at temperatures used for routine vaccines, making it easily implementable and easier to distribute at a global scale through existing infrastructures where vaccines are stored at normal refrigerator temperature. It is also designed to offer the potential to generate high and sustained immune responses, and the potential to prevent virus transmission.

Shots on goal in the fight against the COVID-19 pandemicIn addition to the adjuvanted recombinant protein-based vaccine in collaboration with GSK, Sanofi is developing a messenger RNA vaccine in partnership with Translate Bio. In March 2021, Sanofi and Translate Bio initiated a Phase 1/2 clinical trial of their mRNA COVID-19 vaccine candidate, in order to assess safety, immune response and reactogenicity, after preclinical data showed high neutralizing antibody levels. First results are expected in the third quarter of 2021.

Sanofi is also committed to providing manufacturing support to other vaccine producers. The company recently announced it will manufacture up to 200 million doses of Modernas COVID-19 vaccine for the U.S., starting in September 2021. Earlier this year, Sanofi also announced the company will provide support to BioNTech for 125 million doses for the European Union. In February, Sanofi said it would support Johnson & Johnson for the production of its COVID-19 vaccine at a rate of approximately 12 million doses per month.

In addition to developing its two COVID-19 vaccines, Sanofi is the only company to leverage its manufacturing capacity and expertise for three different COVID-19 vaccines to support the global vaccines supply and help combat the pandemic.

Find out more about our COVID-19 vaccine candidates.

About GSKGSK is a science-led global healthcare company with a special purpose: to help people do more, feel better, live longer. GSK is the leading manufacturer of vaccines globally. For further information please visitwww.gsk.com.



About Sanofi

Sanofi is dedicated to supporting people through their health challenges. Weare a global biopharmaceutical company focused on human health. We preventillness with vaccines, provide innovative treatments to fight pain and easesuffering. We stand by the few who suffer from rare diseases and the millionswith long-term chronic conditions.

With more than 100,000 people in 100 countries, Sanofi is transformingscientific innovation into healthcare solutions around the globe.

Sanofi, Empowering Life

Media Relations ContactsAshleigh Koss Investor Relations Contacts ParisTel: +1 (908) 205-2572 Eva Schaefer-JansenAshleigh.Koss@sanofi.com Arnaud Delepine



Sandrine Guendoul Investor Relations Contacts North AmericaTel.: +33 (0)6 25 09 14 25 Felix LauscherMR@sanofi.com Fara Berkowitz Suzanne Greco

Nicolas KressmannTel.: +1 (732) 532-5318 IR main line:Nicolas.Kressmann@sanofi.com Tel.: +33 (0)1 53 77 45 45 investor.relations@sanofi.com

Sanofi Forward-Looking StatementsThis press release contains forward-looking statements as defined in thePrivate Securities Litigation Reform Act of 1995, as amended. Forward-lookingstatements are statements that are not historical facts. These statementsinclude projections and estimates and their underlying assumptions, statementsregarding plans, objectives, intentions and expectations with respect to futurefinancial results, events, operations, services, product development andpotential, and statements regarding future performance. Forward-lookingstatements are generally identified by the words ?expects?, ?anticipates?,?believes?, ?intends?, ?estimates?, ?plans? and similar expressions. AlthoughSanofi?s management believes that the expectations reflected in suchforward-looking statements are reasonable, investors are cautioned thatforward-looking information and statements are subject to various risks anduncertainties, many of which are difficult to predict and generally beyond thecontrol of Sanofi, that could cause actual results and developments to differmaterially from those expressed in, or implied or projected by, theforward-looking information and statements. These risks and uncertaintiesinclude among other things, the uncertainties inherent in research anddevelopment, future clinical data and analysis, including post marketing,decisions by regulatory authorities, such as the FDA or the EMA, regardingwhether and when to approve any drug, device or biological application that maybe filed for any such product candidates as well as their decisions regardinglabelling and other matters that could affect the availability or commercialpotential of such product candidates, the fact that product candidates ifapproved may not be commercially successful, the future approval and commercialsuccess of therapeutic alternatives, Sanofi?s ability to benefit from externalgrowth opportunities, to complete related transactions and/or obtain regulatoryclearances, risks associated with intellectual property and any related pendingor future litigation and the ultimate outcome of such litigation, trends inexchange rates and prevailing interest rates, volatile economic and marketconditions, cost containment initiatives and subsequent changes thereto, andthe 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, aswell as on our employees and on the global economy as a whole. Any materialeffect of COVID-19 on any of the foregoing could also adversely impact us. Thissituation is changing rapidly, and additional impacts may arise of which we arenot currently aware and may exacerbate other previously identified risks. Therisks and uncertainties also include the uncertainties discussed or identifiedin the public filings with the SEC and the AMF made by Sanofi, including thoselisted under ?Risk Factors? and ?Cautionary Statement Regarding Forward-LookingStatements? in Sanofi?s annual report on Form 20-F for the year ended December31, 2019. Other than as required by applicable law, Sanofi does not undertakeany obligation to update or revise any forward-looking information orstatements.

1 Moyo-Gwete, T. et al. SARS-CoV-2 501Y.V2 (B.1.351) elicits cross-reactive neutralizing antibodies. bioRxiv (2021)

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