-- Ongoing Clinical Program Includes the Phase 3 ENHANCE Study in MDS --

-- Additional Studies Are Evaluating Magrolimab in Both Hematologic and Solid Tumors --

FOSTER CITY, Calif.--(BUSINESS WIRE)-- Gilead Sciences, Inc. (Nasdaq: GILD) today announced that the U.S. Food and Drug Administration (FDA) has granted Breakthrough Therapy designation for magrolimab, a first-in-class, investigational anti-CD47 monoclonal antibody for the treatment of newly diagnosed myelodysplastic syndrome (MDS). MDS is a type of cancer caused by poorly formed or dysfunctional blood cells in the bone marrow. Approximately 15,000 people are diagnosed with MDS in the U.S. each year, and no new treatments have been approved in 14 years. The average survival rate for those with lower-risk MDS is six years and approximately 18 months for those with higher-risk MDS. Breakthrough Therapy designation is designed to expedite the development and regulatory review of investigational treatments for serious or life-threatening conditions that, based on preliminary clinical evidence, have the potential to substantially improve clinical outcomes compared with available therapy. The FDA granted Breakthrough Therapy designation for magrolimab based on positive results of an ongoing Phase 1b study, which evaluated magrolimab in combination with azacitidine in previously untreated intermediate, high and very high-risk MDS. In data presented at the 2020 European Hematology Society Congress, 91 percent of evaluable patients (n=33) treated with magrolimab plus azacitidine achieved an objective response, with 42 percent achieving a complete remission (CR). The combination of magrolimab plus azacitidine was generally well-tolerated. No maximum tolerated dose was reached and no MDS patients discontinued treatment due to a treatment-related adverse event. ?The Breakthrough Therapy designation recognizes the potential for magrolimab to help address a significant unmet medical need for people with MDS and underscores the transformative potential of Gilead?s immuno-oncology therapies in development,? said Merdad Parsey, MD, PhD, Chief Medical Officer, Gilead Sciences. Magrolimab is currently being studied in the double-blind, placebo-controlled, randomized Phase 3 ENHANCE trial in previously untreated higher risk MDS. The trial will evaluate the safety and efficacy of magrolimab, in combination with azacitidine, as measured by CR and duration of CR. Magrolimab is an investigational agent and has not been approved anywhere globally. Its safety and efficacy have not been established. About Magrolimab Magrolimab is a first-in-class investigational monoclonal antibody against CD47 and macrophage checkpoint inhibitor that is designed to interfere with recognition of CD47 by the SIRPa receptor on macrophages, thus blocking the "don't eat me" signal used by cancer cells to avoid being ingested by macrophages. Magrolimab is being developed in several hematologic and solid tumor malignancies, including MDS. Magrolimab has been granted Fast Track Designation by the FDA for the treatment of MDS, acute myeloid leukemia (AML), diffuse large B-cell lymphoma (DLBCL) and follicular lymphoma. Magrolimab has also been granted Orphan Drug Designation by the FDA for MDS and AML and by the European Medicines Agency for AML. Additional information on magrolimab clinical trials is available on?www.clinicaltrials.gov. About Gilead Sciences Gilead Sciences, Inc. is a research-based biopharmaceutical company that discovers, develops and commercializes innovative medicines in areas of unmet medical need. The company strives to transform and simplify care for people with life-threatening illnesses around the world. Gilead has operations in more than 35 countries worldwide, with headquarters in Foster City, California. For more information on Gilead Sciences, please visit the company?s website at?www.gilead.com. Gilead Forward-Looking Statement This press release includes forward-looking statements within the meaning of the Private Securities Litigation Reform Act of 1995 that are subject to risks, uncertainties and other factors, including the risk that FDA and other regulatory agencies may not approve magrolimab for the treatment of MDS and other indications, and any marketing approvals, if granted, may have significant limitations on its use. There is also the possibility of unfavorable results from ongoing and additional clinical studies involving magrolimab, including in combination with azacitidine, and the possibility that Gilead may be unable to initiate and complete future studies involving magrolimab in the anticipated timelines or at all. Further, it is possible that Gilead may make a strategic decision to discontinue development of magrolimab. All statements other than statements of historical fact are statements that could be deemed forward-looking statements. These risks, uncertainties and other factors could cause actual results to differ materially from those referred to in the forward-looking statements. The reader is cautioned not to rely on these forward-looking statements. These and other risks are described in detail in Gilead?s Quarterly Report on Form 10-Q for the quarter ended June 30, 2020, as filed with the U.S. Securities and Exchange Commission. All forward-looking statements are based on information currently available to Gilead, and Gilead assumes no obligation to update any such forward-looking statements.

For more information about Gilead, please visit the company?s website at?www.gilead.com, follow Gilead on Twitter (@GileadSciences) or call Gilead Public Affairs at 1-800-GILEAD-5 or 1-650-574-3000.

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Adam Levy, Investors (347) 446-1488 Marian Cutler, Media (973) 517-0519 Source: Gilead Sciences, Inc.