Gilead Sciences, Inc., founded in 1987 and headquartered in Foster City, California, is a biopharmaceutical company focused on the discovery, development and commercialization of medicines in areas of high unmet medical need. The company initially built its reputation in antiviral therapies and has since expanded into oncology, cell therapy and inflammatory diseases. Gilead operates a global research and commercial organization, conducting clinical development and selling medicines in markets around the world.
Gilead’s product portfolio is anchored by antiviral therapies for HIV and viral hepatitis. Its marketed HIV medicines include combination regimens such as Biktarvy and older franchise products used for treatment and prevention. In hepatitis C, Gilead’s acquisitions and development efforts produced direct-acting antivirals including sofosbuvir-based regimens marketed under names such as Sovaldi, Harvoni and Epclusa. During the COVID-19 pandemic Gilead’s antiviral remdesivir (Veklury) became one of the first therapies authorized for treatment of hospitalized patients. In oncology and cell therapy, Gilead strengthened its pipeline and commercial footprint through acquisitions—most notably the purchase of Kite Pharma, which added CAR-T therapies including Yescarta and Tecartus, and the acquisition of Immunomedics, which added the antibody–drug conjugate Trodelvy—illustrating the company’s strategic shift to diversify beyond traditional antivirals.
Historically, Gilead has grown through a combination of internal R&D and targeted acquisitions, including Pharmasset in 2011 (which accelerated its hepatitis C program) and later transactions that broadened its oncology and cell therapy capabilities. The company maintains research centers and commercial operations across North America, Europe, Asia and other regions, serving a global patient population. Michael L. Riordan founded Gilead, and the company’s executive leadership in recent years has overseen the transition from a primarily antivirals-focused developer to a broader biopharma company; as of mid-2024, Daniel O’Day was serving as the company’s chief executive. Gilead continues to invest in clinical development and strategic partnerships to expand its therapeutic offerings and address emerging medical needs.