Gilead Sciences

In March 1999, Gilead acquired NeXstar Pharmaceuticals of Boulder, Colorado. At the time, NeXstar's annual sales of $130 million was three times Gilead's sales; it sold AmBisome, an injectable fungal treatment, and DaunoXome, an oncology drug taken by HIV patients. That same year, Roche announced FDA approval of Tamiflu (oseltamivir) for the treatment of influenza. Tamiflu was originally discovered by Gilead and licensed to Roche for late-phase development and marketing.

One reason for entering into the Tamiflu licensing agreement was that with only 350 employees, Gilead still did not yet have the capability to sell its drugs directly to overseas buyers. To avoid having to license future drugs in order to access international markets, Gilead simply acquired the 480-employee NeXstar, which had already built its own sales force in Europe to market AmBisome there.

2000 to 2009

Viread (tenofovir) achieved first approval in 2001 for the treatment of HIV.

In 2002, Gilead changed its corporate strategy to focus exclusively on antivirals, and sold its cancer assets to OSI Pharmaceuticals for $200 million. In December 2002, Gilead and Triangle Pharmaceuticals announced that Gilead would acquire Triangle for around $464 million; Triangle's lead drug was emtricitabine that was near FDA approval, and it had two other antivirals in its pipeline. The company also announced its first full year of profitability. Later that year, Hepsera (adefovir) was approved for the treatment of chronic hepatitis B, and Emtriva (emtricitabine) for the treatment of HIV.

During this era, Gilead completed its gradual evolution from a biotech startup into a pharmaceutical company. The San Francisco Chronicle noted that by 2003, the Gilead corporate campus in Foster City had expanded to "seven low-slung sand-colored buildings around a tiny lake on which ducks happily paddle." Like many startups, Gilead originally leased its space, but in 2004, the company paid $123 million to buy all its headquarters buildings from its landlords. However, even as Gilead developed its ability to distribute and sell its own drugs, it remained distinct from most pharmaceutical companies in terms of its strong reliance on subcontracting most of its manufacturing to contract manufacturing organizations.

In 2004, during the Avian flu pandemic scare, Gilead Sciences' revenue from Tamiflu almost quadrupled to $44.6m as more than 60 national governments stockpiled the antiviral drug, though the firm had made a loss in 2003 before concern about the flu started. As stocks soared, US Defense Secretary and Pentagon chief Donald Rumsfeld sold shares of the company, receiving more than $5 million in capital gains, while still maintaining up to $25m-worth of shares by the end of the year. Sales of Tamiflu almost quadrupled again in 2005, to $161.6m, during which time the share price tripled. A 2005 report showed that, in all, Rumsfeld owned shares worth up to $95.9m, from which he got an income of up to $13m.

In 2006, the company acquired Corus Pharma, Inc. for $365 million. The acquisition of Corus signaled Gilead's entry into the respiratory arena. Corus was developing aztreonam lysine for the treatment of patients with cystic fibrosis who are infected with Pseudomonas aeruginosa. In July 2006, the U.S. Food and Drug Administration (FDA) approved Atripla, a once a day single tablet regimen for HIV, combining Sustiva (efavirenz), a Bristol-Myers Squibb product, and Truvada (emtricitabine and tenofovir disoproxil), a Gilead product.

Gilead purchased Raylo Chemicals, Inc. in November 2006, for a price of US$133.3 million. Raylo Chemical, based in Edmonton, Alberta, was a wholly owned subsidiary of Degussa AG, a German company. Raylo Chemical was a custom manufacturer of active pharmaceutical ingredients and advanced intermediates for the pharmaceutical and biopharmaceutical industries.

Later in the same year, Gilead acquired Myogen, Inc. for $2.5 billion (then its largest acquisition). With two drugs in development (ambrisentan and darusentan), and one marketed product (Flolan) for pulmonary diseases, the acquisition of Myogen has solidified Gilead's position in this therapeutic arena. Under an agreement with GlaxoSmithKline, Myogen marketed Flolan (epoprostenol sodium) in the United States for the treatment of primary pulmonary hypertension. Additionally, Myogen was developing (in Phase 3 studies) darusentan, also an endothelin receptor antagonist, for the potential treatment of resistant hypertension.

Gilead expanded its move into respiratory therapeutics in 2007 by entering into a licensing agreement with Parion for an epithelial sodium channel inhibitor for the treatment of pulmonary diseases, including cystic fibrosis, chronic obstructive pulmonary disease and bronchiectasis.

In 2009, the company acquired CV Therapeutics, Inc. for $1.4 billion, bringing Ranexa and Lexiscan into Gilead. Ranexa is a cardiovascular drug used to treat chest pain related to coronary artery disease, with both of these products and pipeline building out Gilead's cardiovascular franchise. Later that year, the company was named one of the Fastest Growing Companies by Fortune.

2010 to 2019

In 2010, the company acquired CGI Pharmaceuticals for $120 million, expanding Gilead's research expertise into kinase biology and chemistry. Later that year, the company acquired Arresto Biosciences, Inc. for $225 million, obtaining developmental-stage research for treating fibrotic diseases and cancer.

In February 2011, the company acquired Calistoga Pharmaceuticals for US$375 million ($225 million plus milestone payments). The acquisition boosted Gilead's oncology and inflammation areas. Later that year, Gilead made its most important acquisition – and by then most expensive – with the US$10.4 billion purchase of Pharmasset, Inc. This transaction helped cement Gilead as the leader in treatment of the hepatitis C virus by giving it control of sofosbuvir (see below).

In October 2011, Gilead broke ground on a massive multi-year expansion of its 17-building headquarters campus in Foster City. By replacing eight one or two-story buildings with seven new structures ranging as tall as 10 stories, Gilead nearly doubled its headquarters real estate footprint from about 620,000 square feet to about 1.2 million square feet.

On July 16, 2012, the FDA approved Gilead's Truvada for prevention of HIV infection (it was already approved for treating HIV). The pill was a preventive measure (PrEP) for people at high risk of getting HIV through sexual activity.

In 2013, the company acquired YM Biosciences, Inc. for $510 million. The acquisition brings drug candidate CYT387, an orally administered, once-daily, selective inhibitor of the Janus kinase (JAK) family, specifically JAK1 and JAK2, into Gilead's oncology pipeline. The JAK enzymes have been implicated in myeloproliferative diseases, inflammatory disorders, and certain cancers.

In 2015, the company made a trio of acquisitions:

It bought Phenex Pharmaceuticals for $470 million. Its Farnesoid X receptor (FXR) program used small-molecule FXR agonists in the treatment of liver diseases such as non-alcoholic steatohepatitis.

It bought EpiTherapeutics for $65 million. This acquisition gave Gilead first-in-class small molecule inhibitors of histone demethylases involved in regulating gene transcription in cancer.

It paid $425 million for a 15% equity stake in Galapagos NV, with additional payments for Gilead to license the experimental anti-inflammatory drug filgotinib, which may treat rheumatoid arthritis, ulcerative colitis, and Crohn's disease.

In 2016, the company acquired Nimbus Apollo, Inc. for $400 million, giving Gilead control of the compound NDI-010976 (an ACC inhibitor) and other preclinical ACC inhibitors for the treatment of non-alcoholic steatohepatitis and for the potential treatment of hepatocellular carcinoma. Also in 2016, the company was named the most generous company on the 2016 Fortune list of The Most Generous Companies of the Fortune 500. Charitable donations to HIV/AIDS and liver disease organizations totaled over 440 million in 2015.

In August 2017, the company announced it would acquire Kite Pharma for $11.9 billion, equating to $180 cash per share, a 29% premium over the closing price of the shares. The deal was Gilead's entry into the cell therapy market and added a chimeric antigen receptor T cell (CAR-T) therapy candidate to the company's portfolio. By 2022 this acquisition had led to two marketed products for lymphoma: Yescarta and Tecartus. In November, the company announced it will acquire Cell Design Labs for up to $567 million, after it indirectly acquired a stake of 12.2% via the Kite Pharma deal.

On May 9, 2019, the U.S. Department of Health and Human Services announced that Gilead Sciences will donate Truvada, the only drug approved to prevent infection with H.I.V., for free to 200,000 patients annually for 11 years. On December 3, 2019, HHS explained how the government would distribute the donated drugs. HHS Secretary Alex Azar explained that the U.S. government will pay Gilead $200 per bottle for 30 pills for costs associated with getting the drug from factories into the eventual hands of patients.

Gilead Sciences is led by a board of directors and an executive management team. Daniel O'Day has served as the chairman and chief executive officer since 2019. He succeeded John F. Milligan who was CEO from 2016 to 2018 and John C. Martin, who held the CEO role from 1996 to 2016, and was chairman until 2018.

2020-

In March 2020, the company announced it would acquire Forty Seven Inc. for $95.50 a share ($4.9 billion in total). On April 7, 2020, Gilead completed acquisition of Forty Seven, Inc. for "$95.50 per share, net to the seller in cash, without interest, or approximately $4.9 billion in the aggregate."

In June 2020, Bloomberg reported that AstraZeneca Plc had made a preliminary approach to Gilead for a potential merger, worth almost $240 billion. In the same month, the company announced it would acquire a 49.9% stake in privately held Pionyr Immunotherapeutics Inc for $275 million. In September 2020, Gilead announced it had reached a deal to acquire Immunomedics for $21 billion ($88 per share), gaining control of the cancer treatment Trodelvy (Sacituzumab govitecan-hziy) – a first-in-class Trop-2 antibody-drug conjugate. In December, the business announced it would acquire German biotech, MYR GmbH, for €1.15 billion plus up to a further €300 million. MYR focuses on the treatment of chronic hepatitis delta virus.

In November 2021, the company was added to the Dow Jones Sustainability World Index. In January 2022, Gilead pulled its cancer drug Zydelig (idelalisib) from its accelerated approval in relapsed follicular B-cell non-Hodgkin lymphoma (FL) and relapsed small lymphocytic leukemia (SLL). In September, the company completed its acquisition of MiroBio for $405 million. In February 2023, the business, through Kite Pharma completed its acquisition of Tmunity Therapeutics. In May, the business announced it would acquire XinThera and its small molecule inhibitors. In February 2024, the company acquired CymaBay Therapeutics, and in September, paid Genesis Therapeutics $35 million for AI-based drug discovery work.

In May 2025, Gilead Sciences announced it would pay $10 million for sole ownership of arenavirus immunotherapies for hepatitis B (HBV) and HIV resulting from the company's collaboration with Hookipa Pharma.

In December 2025, it was announced that Gilead Sciences had agreed to acquire RP-3467, a polymerase theta (Polθ) ATPase inhibitor, from Repare Therapeutics for total consideration of up to US$30 million. The agreement includes an upfront payment of US$25 million and up to an additional US$5 million contingent on the completion of specified technology transfer activities.

Throughout 2024 and 2025, Gilead invested in AI-based drug discovery and continued to focus on immunotherapy research and development. This included a collaboration with Hookipa Pharma for arenavirus immunotherapies for hepatitis B and HIV. In 2025, Gilead reported it would invest $32 billion in U.S. research, development, and manufacturing through 2030.

Truvada and Descovy

Truvada was introduced to the market by Gilead in 2004 to treat HIV infections. In the following years, the United States government conducted research demonstrating that Truvada was able to prevent HIV infection. The US Centers for Disease Control holds the patent for this use of Truvada as pre-exposure prophylaxis (PreP).

Gilead introduced Truvada for PreP in 2012, at which point a prescription cost approximately $1,200 per month in the United States. By 2018, this price had increased to up to $2,000, despite generally costing less than $100 outside the U.S. Gilead made over $3 billion in sales of Truvada in 2018.

The high price drew the ire of activist groups such as ACT UP and was the subject of a Congressional hearing in May 2019. Gilead's CEO defended its pricing in the hearing by noting the large sums the company spends on HIV/AIDS research. Activists pressured the US government to enforce its patent on Truvada in order to combat the high prices set by Gilead.

In May 2019, Gilead announced it would donate enough Truvada to treat up to 200,000 patients annually for up to 11 years, the result of discussions with the Department of Health and Human Services under Trump. Dr. Rochelle Walensky noted that the donations still covered less than one-fifth of the people who need the drug, and argued it was possibly a move to help the company market Descovy, a more advanced successor drug. Walensky led a 2020 study that concluded the high costs of Descovy would on the whole negate any comparative advantage of prescribing it over a generic Truvada alternative.

In July 2021, Gilead announced it would decrease 340B Drug Pricing Program reimbursements to clinics serving primarily low-income communities; clinics argued this severely hinders their ability to provide HIV/AIDS prevention and treatment services among vulnerable populations.

Anticompetitive behavior

Gilead has also been accused of stifling competition. A lawsuit filed in the United States in 2019 alleged that the company entered "pay for delay" agreements with other manufacturers, wherein the manufacturers agreed to delay releasing generic versions of Truvada. In 2021, CVS Pharmacy and Rite Aid filed a lawsuit on similar grounds against Gilead, Bristol-Myers Squibb, and Teva Pharmaceuticals in 2021.

In response to criticisms over the price of Sovaldi, Gilead began licensing the rights to produce generic versions of the drug to select producers in India in 2015. Included in the licensing agreements were 'anti-diversion' provisions, designed to prevent the drug from being exported back to developed countries where the cheaper, generic alternatives were still unavailable. (In India, a one-month treatment cost approximately US$300, versus $1,000 per pill in the United States.) Gilead required the Indian producers to screen patients to determine who could buy Sovaldi, which was criticized by Médecins Sans Frontières since it could lead to the exclusion of vulnerable groups like refugees and migrants from accessing the medicines. In response to the criticism, Gilead eventually relaxed these requirements.

Tax structures and tax avoidance

Gilead has been criticized for tax avoidance. Tax avoidance, as opposed to tax evasion, is the use of legal means to shift tax burdens from the one jurisdiction to overseas affiliates that pay a lower tax rate, even if revenue is primarily generated outside the overseas jurisdiction.

A 2016 report by the liberal think tank Americans for Tax Fairness argued that Gilead was able to avoid up to $10 billion in taxes on U.S. sales through mechanisms such as transfer pricing, the sale of assets between affiliated entities. In particular, Gilead sells intellectual property to an Irish subsidiary, which then sells the finished products, such as Sovaldi, in the United States and elsewhere, paying the low Irish tax rate on profits. The practice is common among multinational pharmaceutical companies like Gilead.

On December 26, 2018, The Times reported that Gilead had used the Double Irish arrangement to avoid U.S. corporate taxes on global profits, stating that the firm "used a controversial tax loophole arrangement to shift almost €20 billion in profits through an Irish entity in just two years" without paying Irish taxes. The company repatriated a portion of the Irish subsidiary's holdings, $28 billion, to the United States in 2018 following reductions of the corporate tax rate. For this it paid an estimated $5.5 billion in tax.

Regulatory approval

Veklury received approval from the US Food and Drug Administration (FDA) in October 2020 use in hospitalized adults and children 12 years and older for treatment of severe COVID-19 infections. In January 2022, the FDA gave regulatory approval to Veklury for use in adults and children (12 years of age and older who weigh at least 40 kilograms (88 lb) and are positive for COVID-19, not hospitalized, and are ill having high risk for developing severe COVID-19, including hospitalization or death.

The FDA also provided Emergency Use Authorization for Veklury treatment of children under age 12 who are COVID-positive and not hospitalized, but have mild-to-moderate COVID-19 with high risk of developing severe COVID-19, including hospitalization or death.