Gilead Sciences, Inc.
CorpDigest
Gilead Sciences, Inc.
Company History
Founded 1987 in Foster City, California
Last reviewed: 2026-06-08 · By Swet Parvadiya
In the cell therapy space, the company faces intense competition from Bristol Myers Squibb, which has launched Abecma and Carvykti in the multiple myeloma space, and from a new wave of allogeneic cell therapy companies that are attempting to eliminate the complex autologous manufacturing process. The origin of Gilead Sciences, Inc. is not a single founding moment but a complex evolution of scientific discovery, entrepreneurial ambition, and the brutal economics of the global antiviral market. The story begins in 1987 when Michael L. Riordan, a physician and entrepreneur, founded the company in Foster City, California, with an initial focus on developing antifungal therapies for life-threatening infections.
Michael L. Riordan is an American physician and entrepreneur who founded Gilead Sciences in 1987 and served as its CEO until 1993. He played a pivotal role in the company's early survival, navigating the severe cash crunch of the early 1990s and executing the 1992 IPO that saved the company from bankruptcy. Riordan's background as a medical doctor gave him a unique perspective on the pharmaceutical industry, driving his focus on developing therapies for life-threatening infections where patient needs were greatest. During his tenure, he oversaw the acquisition of the rights to AmBisome, which provided the company with its first commercial product and a steady stream of revenue to fund internal discovery efforts. After stepping down as CEO, Riordan remained active in the biotechnology community, serving on the boards of several major pharmaceutical companies and continuing to invest in early-stage life science startups. He is widely respected in the industry for his role in creating a global biopharmaceutical powerhouse and for his commitment to bringing novel therapies to patients with limited treatment options.
Michael L. Riordan founded Gilead Sciences in Foster City, California, with an initial focus on developing antifungal therapies for life-threatening infections.
Gilead Sciences executed a desperate IPO that raised $86 million, providing the necessary lifeline to continue operations and pivot to antivirals after facing a severe cash crunch.
The FDA approved Viread (tenofovir disoproxil fumarate), the first once-daily nucleotide reverse transcriptase inhibitor for HIV, marking the beginning of Gilead's ascent to the top of the global virology hierarchy.
Gilead acquired Triangle Pharmaceuticals for $464 million, securing the rights to emtricitabine, which was combined with tenofovir to create Truvada, the most successful HIV prevention and treatment regimen in history.
Gilead acquired Pharmasset for $11 billion, securing the nucleotide analog platform responsible for Sovaldi and Harvoni, which generated over $50 billion in cumulative revenue.
Gilead acquired Kite Pharma for $11.9 billion, establishing a dominant position in autologous CAR-T cell therapy with Yescarta and expanding its presence in oncology.
Gilead acquired Immunomedics for $21 billion, securing the Sacituzumab govitecan (Trodelvy) platform and establishing a dominant position in the antibody-drug conjugate (ADC) space.
Gilead reported $28.5 billion in product sales for FY2024, with operating income reaching $10.2 billion and free cash flow at $9.8 billion, demonstrating strong performance post-Veklury decline.
Gilead announced the results of the PURPOSE 1 trial, demonstrating 100% efficacy for lenacapavir in preventing HIV acquisition in cisgender women, a landmark result in HIV prevention.
Gilead acquired Immunomedics for $21 billion to gain control of the Sacituzumab govitecan (Trodelvy) ADC platform, establishing a dominant position in solid tumor oncology.
Gilead acquired Kite Pharma for $11.9 billion to establish a dominant position in autologous CAR-T cell therapy with Yescarta and expand its presence in oncology.
Gilead acquired Pharmasset for $11 billion to secure the nucleotide analog platform responsible for Sovaldi and Harvoni, the curative hepatitis C therapies.
Gilead acquired Forty Seven for $4.9 billion to gain control of the CD47 blocker magrolimab, a novel oncology asset targeting myelodysplastic syndromes and acute myeloid leukemia.
By 1992 Gilead faced a severe cash crunch that threatened its survival, having burned through capital while developing early antifungal and antisense programs. The company executed an IPO in 1992 that raised roughly $86 million, providing the lifeline needed to pivot decisively toward antiviral drug discovery.
In 2001 the FDA approved Viread (tenofovir disoproxil fumarate), the first once-daily nucleotide reverse transcriptase inhibitor for HIV. That approval launched Gilead's ascent in virology and became the chemical backbone for later blockbuster single-tablet regimens including Truvada and Biktarvy.
Gilead launched the hepatitis C cure Sovaldi in 2013 and Harvoni in 2014, and the franchise generated more than $50 billion in cumulative revenue between 2014 and 2018. At its peak the hepatitis C market produced over $30 billion in annual sales before the curative nature of the drugs shrank the treatable patient pool.
Veklury (remdesivir) launched in 2020 as a COVID-19 antiviral and peaked at about $5.5 billion in FY2022 sales. As the pandemic transitioned to an endemic phase and government procurement contracts expired, Veklury sales declined by more than 80%, leaving a revenue void the oncology portfolio is now filling.
In 2011 Gilead acquired Pharmasset for approximately $11 billion to secure the nucleotide analog platform behind Sovaldi and Harvoni. The move transformed Gilead from a niche antiviral player into a hepatitis C powerhouse and funded a decade of subsequent transformational acquisitions.