The 2025 Warren Alpert Foundation Prize has been awarded to three scientists whose discoveries culminated in the development of lenacapavir, a medication used to treat and prevent human immunodeficiency virus (HIV) and the first approved drug to disrupt a viral capsid, a critical piece of the viral machinery that allows it to replicate.

Because this therapy, more potent than any other HIV drug, is given only twice a year and can prevent HIV infection, it carries the promise to accelerate the end of the HIV epidemic.

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The $500,000 award, to be shared among the three winners, is given by the Warren Alpert Foundation in recognition of work that has improved the understanding, prevention, treatment, or curing of human disease. The prize is administered by Harvard Medical School. The award winners will be recognized at a scientific symposium on Oct. 30 hosted by Harvard Medical School. For details, visit the Warren Alpert Foundation Prize symposium website.

“Lenacapavir is a powerful example of how basic research that elucidates the structure and behavior of a virus can lead to life-changing treatments,” said George Q. Daley, dean of Harvard Medical School and chair of the Warren Alpert Foundation Prize advisory board. “It reflects the best of academic-industry collaboration and marks a major step toward ending a decades-long epidemic.”

Significance of the work

About 40 million people worldwide are living with HIV, according to the World Health Organization. Despite the availability of effective antiviral medications that make HIV a manageable chronic condition, more than 1.3 million new infections occur each year, and more than 600,000 people die from HIV complications every year. Barriers that hamper access to treatments and preventive measures — as well as a persistent stigma in using them — remain serious challenges to minimizing the casualties of the virus and ending the global epidemic caused by it.

The three scientists honored with this year’s Warren Alpert Foundation Prize each played key distinct and complementary roles toward developing ways to target therapeutically the HIV capsid — the cone-shaped protein shell that protects the viral RNA genome and the enzymes needed for its replication. Based on these insights, they developed a revolutionary drug called lenacapavir that blocks the myriad functions of the HIV capsid throughout the viral replication cycle, stymieing the virus’s ability to multiply in cells. Because of its extreme potency and stability, lenacapavir only needs to be administered every six months, ridding patients of the burden of daily dosing necessary for other HIV-fighting drugs.

The drug has shown high efficacy in preventing HIV transmission and infection, and could, therefore, play a pivotal role in ending the HIV epidemic – a goal that the World Health Organization and the Joint United Nations Programme on HIV/AIDS (UNAIDS) aim to meet by 2030. In a recent clinical trial of 5,000 adolescent girls and young women in South Africa and Uganda, twice-yearly injections of lenacapavir were found to be 100 percent effective in preventing HIV infection.

“Lenacapavir isn’t just a transformative medicine, it’s a game changer,” said David M. Hirsch, director and chairman of the board of the Warren Alpert Foundation. “Removing the burden of daily pills, this twice-yearly injection gives us a real shot at stopping HIV transmission and turning the tide on the HIV epidemic. This truly captures the spirit of the Warren Alpert Foundation.”

From the winners

“It’s a great honor to be recognized by Harvard Medical School and the Warren Alpert Foundation and to join the distinguished ranks of past Alpert Prize recipients, who are a highly accomplished and inspirational group. It is also a privilege to represent the many other basic researchers, both in our lab and in other labs, who have contributed to our understanding of the HIV capsid. Finally, it’s wonderful to share the honor with Tomas Cihlar, John Link, and Gilead, who did amazing work in developing lenacapavir.” – Wesley Sundquist

“It is a humbling experience and tremendous honor considering the relevance of the Prize and all its prior recipients, many of whom are role models and a source of great inspiration for me as a scientist. It is also a great privilege to be recognized together with two of my collaborators for many years. But first and foremost, it is a recognition of many scientists, physicians, community workers, and participants in our clinical studies who all played an important part in the discovery and development of lenacapavir.” – Tomas Cihlar

“It is an honor for me to be selected for the prestigious Warren Alpert Foundation Prize with Tomas Cihlar and Wesley Sundquist, and it is deeply meaningful to be part of the team that discovered lenacapavir. The prize is an important recognition of the role of chemistry in the creation of this lifesaving medicine. Lenacapavir’s potential for accelerating the end of the HIV epidemic is beyond what any of us could have imagined in those earliest days.” – John O. Link