GILD

The company was founded in June 1987 by Michael Riordan, a young physician and venture investor, originally under the name Oligogen, a reference to the oligonucleotide chemistry the early business intended to pursue. It was soon renamed Gilead, after a region referenced in the Bible as a source of medicinal balm. The company went public in 1992 and spent its first decade as a research focused antiviral specialist, producing the influenza drug Tamiflu, which it licensed to Roche, and the antiviral Vistide. The defining strategic choice of the early 2000s was to concentrate on HIV. Gilead developed tenofovir and combined it with emtricitabine to create Truvada, then folded that backbone into single tablet regimens. Atripla, approved in 2006, was the first once daily single pill for HIV and established the template that has governed the franchise ever since, namely combining multiple agents into one convenient, well tolerated, long patent protected product.

The chapter that made Gilead a household name in financial circles was hepatitis C. In late 2011 the company agreed to acquire Pharmasset for roughly 11 billion dollars, a price that looked aggressive at the time and was widely questioned. Pharmasset owned sofosbuvir, which Gilead launched as Sovaldi in late 2013 and then improved into the combination pill Harvoni. These drugs cured hepatitis C in a matter of weeks with few side effects, replacing older regimens that were long, harsh, and only partially effective. The commercial response was extraordinary. United States sales of Sovaldi and Harvoni totaled more than 20 billion dollars in the roughly 21 months after launch, and the products triggered a national debate over drug pricing, including a United States Senate investigation into the 84,000 dollar list price of a course of treatment. The same feature that made the drugs valuable, a genuine cure, also capped their commercial life. Each cured patient left the treatable pool, the warehouse of untreated patients drained faster than expected, competition from AbbVie and others pushed prices down, and hepatitis C revenue fell from its mid 2010s peak by a large margin over the following years. The episode is the clearest illustration of a structural fact about Gilead, namely that a cure is a worse business than a chronic therapy, and that the company has repeatedly had to replace large revenue streams rather than compound them.

HIV is the franchise that does compound, and it is the economic engine of the company. Gilead treats a large share of people living with HIV in the developed world through its single tablet regimens, and the franchise is anchored by Biktarvy, which by the mid 2020s accounted for close to half of total product sales. The durability comes from several reinforcing advantages. Patents and regulatory exclusivity protect the specific combinations and formulations. Switching costs are high because patients on a working regimen are reluctant to change. Decades of clinical data give physicians confidence in Gilead's products as the default standard of care. And the company controls the full chain from the active molecules to the finished combination pill. The most important near term opportunity sits on the prevention side. Truvada was approved for pre exposure prophylaxis, known as PrEP, in 2012, and Descovy later took share in that market. In June 2025 the United States Food and Drug Administration approved lenacapavir, sold as Yeztugo, as the first twice yearly injectable option for HIV prevention. In the pivotal trials it reduced new infections dramatically relative to a daily oral comparator, and a dosing schedule of two injections a year addresses the adherence problem that limits the real world effectiveness of daily pills. Gilead has framed Yeztugo as a way to enlarge the PrEP market itself, projecting that the United States PrEP population could grow from roughly 400,000 people toward more than a million by the middle of the next decade, with the company expecting to hold a majority share. Outside analysts have estimated multibillion dollar peak annual sales for the product. Lenacapavir is also being developed in longer acting treatment combinations, which matters because Biktarvy loses key patent protection around 2033 and the company needs a next generation backbone to defend the franchise into the 2030s.

Oncology is the diversification bet, and it has been expensive and uneven. In 2017 Gilead acquired Kite Pharma for roughly 11.9 billion dollars to enter cell therapy, the approach that engineers a patient's own immune cells to attack cancer. Kite, which operates as Gilead's cell therapy unit, brought the CAR T therapies later marketed as Yescarta for large B cell lymphoma and follicular lymphoma and Tecartus for mantle cell lymphoma and certain leukemias. These therapies are clinically powerful but commercially difficult, requiring specialized treatment centers, complex manufacturing of a bespoke product for each patient, and significant safety monitoring, and their sales growth has been slower and flatter than Gilead hoped. The company has worked to shorten manufacturing timelines and is pursuing newer targets such as a BCMA directed therapy for multiple myeloma. In 2020 Gilead acquired Immunomedics for roughly 21 billion dollars, gaining Trodelvy, a Trop 2 directed antibody drug conjugate that delivers chemotherapy to tumor cells. Trodelvy has grown, particularly outside the United States and in breast cancer, but it has also disappointed in some trials and absorbed accounting impairments along the way. The honest read on Gilead's oncology effort as of 2025 is that the company has bought its way into two important modalities at a high cost, has real approved products, and has not yet proven that the segment can become a third durable pillar alongside HIV and the residual liver disease business.

A separate chapter that briefly mattered a great deal was COVID-19. Gilead's antiviral remdesivir, sold as Veklury, became an early authorized treatment for hospitalized patients and generated more than 4.5 billion dollars in 2021. That revenue has since fallen sharply as the pandemic eased, which fits the recurring Gilead pattern of a large but temporary windfall from an antiviral, useful for funding the rest of the business but not a foundation to build on.

Leadership reflects a deliberate shift in posture. Daniel O'Day became Chairman and Chief Executive Officer in 2019 after a long career at Roche, where he led the pharmaceutical division of a company with deep oncology expertise. His hiring signaled the board's intent to push Gilead beyond its antiviral comfort zone into cancer, and his tenure has been defined by integrating the Kite and Immunomedics acquisitions, advancing the lenacapavir program, and managing the long decline of hepatitis C. Andrew Dickinson serves as Chief Financial Officer, and research and development sits under senior scientific leadership focused on the virology and oncology pipelines. The company is run as a cash generative commercial business that recycles HIV profits into acquisitions and late stage development rather than as a sprawling diversified pharmaceutical conglomerate, and its capital allocation has leaned heavily on dealmaking to acquire assets it could not generate internally fast enough.

Competition varies sharply by area. In HIV, the principal rival is ViiV Healthcare, the venture majority owned by GSK, which has pushed long acting injectable treatment and prevention and competes directly with Gilead's strategy of converting the franchise from daily pills to longer acting regimens. In hepatitis C the market is mature and price competitive, with AbbVie the main competitor. In cell therapy, Gilead's Kite competes with Novartis, Bristol Myers Squibb, and others, and faces the broader question of whether CAR T can move into earlier lines of treatment and larger patient populations. In antibody drug conjugates and broader oncology, Gilead is one entrant among many large and well funded players, including AstraZeneca and Daiichi Sankyo, in a crowded and fast moving field.

The risks are specific and largely structural. The most important is concentration. A business that depends on HIV for roughly half its product sales, and on Biktarvy in particular, is exposed to the 2033 patent cliff, to pricing and rebate pressure in the United States, and to the success or failure of the lenacapavir based regimens meant to carry the franchise forward. Drug pricing policy is a standing threat, both from the negotiation provisions affecting older high revenue products and from the political sensitivity that the hepatitis C pricing fight demonstrated. Pipeline and clinical risk is real, since each acquired oncology asset carries the chance of trial failures and further impairments. Acquisition risk follows from the strategy itself, because a company that buys growth can overpay, as critics argued about both Pharmasset and Immunomedics. And there is the recurring pattern visible across hepatitis C and COVID-19, namely that some of Gilead's biggest successes are inherently temporary, which raises the bar for what the durable HIV core and the unproven oncology bets must deliver.

The forward question for an investor reading this page is whether Gilead can convert a dominant but maturing HIV franchise into a durable second act before its anchor product loses protection. The company has clear strengths, a defensible and highly profitable HIV business, strong cash generation, and in Yeztugo a credible chance to expand the prevention market it already leads. It also carries clear liabilities, a heavy reliance on a single therapeutic area, a 2033 patent cliff on its largest product, and an oncology platform that has cost tens of billions of dollars without yet proving it can stand on its own. The interplay between the lenacapavir opportunity on one side and the Biktarvy cliff on the other is the central tension that will determine whether Gilead Sciences, Inc. remains a steady cash machine, becomes a genuinely diversified cancer and virology company, or slides into the slow decline that eventually follows any franchise built on patents that expire.