Daniel O’Day is Chairman and Chief Executive Officer of Gilead Sciences, a global biopharmaceutical company headquartered in Foster City, California, known for its research, development and delivery of medicines for viral diseases, oncology and other serious conditions. He was appointed CEO in March 2019, bringing more than three decades of leadership experience in the biopharmaceutical sector, including senior executive roles at Roche Pharmaceuticals across multiple regions. O’Day serves on the boards of the Pharmaceutical Research and Manufacturers of America (PhRMA) and Georgetown University.
Under O’Day’s leadership, Gilead has continued to strengthen its position in HIV treatment and prevention, achieving U.S. regulatory approval in 2025 for a twice‑yearly injectable HIV prevention therapy, lenacapavir (marketed as Yeztugo), which is seen as a milestone in HIV prevention and has generated significant global attention. The company has also pursued strategic efforts to expand access to this therapy through licensing agreements and partnerships aimed at reaching high‑incidence, resource‑limited countries. Gilead’s broader portfolio performance includes continued growth in key therapeutic areas such as HIV and oncology, and the company has bolstered global health equity initiatives tied to access, advocacy and innovation under his tenure.
The 100 CEOs featured here reflect the diversity and complexity of modern oncology leadership. In 2025, some lead the world’s largest cancer institutions; others guide specialized societies or emerging innovators. What unites them is responsibility: for millions of patients, for the integrity of science, and for the future direction of cancer care globally.
This list is not a celebration of power, but a recognition of stewardship, accountability, and impact – and of the leaders whose choices continue to shape the fight against cancer. For the many deserving individuals not mentioned in this list, we will continue to acknowledge, honor and elevate your voices in our daily publications from across the world.
See the full list of The 100 Influential CEOs in Oncology in 2025 and stay tuned for other special category nominations
