Scientifically, lenacapavir PrEP takes a victory lap. But now worries about access | AIDS 2026

Lenacapavir for pre-exposure prophylaxis (PrEP) is taking something of a victory lap with more positive results from the open-label extensions of the studies that established the twice-a-year injectable as safe and effective.

The results, shared by researchers at a press conference held last week and scheduled to be presented this week at AIDS 2026, the 26th International AIDS Conference in Rio de Janeiro, Brazil, showed no new HIV infections in the PURPOSE 1 trial that enrolled cisgender women and one new infection in the PURPOSE 2 trial that enrolled cisgender men and gender-diverse individuals. Adherence among the cisgender women was 96% at week 52. Among cisgender men and gender-diverse individuals, it was 96% and 92% at weeks 26 and 52, according to the abstracts that the researchers presented. Lead author Noah Kiwanuka, M.B.Ch.B., M.P.H., Ph.D., an associate professor at the Makerere University of Public Health in Kampala, Uganda, who presented the PURPOSE 1 results, said there are no new safety concerns in the PURPOSE 1 open-label extension. Marcelo Losso, M.D., chief of the emerging disease unit at Hospital General de Agudos José María Ramos Mejía in Buenos Aires, Argentina, who presented the PURPOSE 2 results, reported that there were no new safety signals.

“Together these studies confirm that twice yearly lenacapavir for HIV prevention is safe and highly effective and adherence is high,” Beatriz Grinsztejn, M.D., Ph.D., a leading Brazilian AIDS clinician and researcher and president of the International AIDS Society (IAS), the sponsor of the AIDS 2026 conference, said during the press conference. “Now we must accelerate efforts to deliver this extraordinary advance to those who need it most.” Grinsztejn is one of the co-authors of the abstract summarizing the Purpose 2 open-label extension that is being presented at the meeting.

When positive results for lenacapavir for PrEP were presented at the 2024 version of the IAS conference, they were celebrated as marking a turning point in the efforts to curb the transmission of HIV and possibly end AIDS as a public health threat. With ambitions for developing an HIV vaccine still unrealized, long-acting PrEP assumed the mantle as the safest and most effective to prevent HIV infection. The journal Science anointed lenacapavir its 2024 Breakthrough of the Year. At a press conference today, Winnie Byanyima, executive director of the Joint United Nations Programme on HIV/AIDS (UNAIDS), said lenacapavir and other HIV prevention modalities are “approaching vaccine-like effectiveness."

But there is a gap between the heady potential of PrEP with lenacapavir and the current reality partly because the drug is in short supply in some countries with significant HIV transmission. In a recent interview with Managed Healthcare Executive (MHE), Lloyd Mulenga, M.B.Ch.B., Ph.D., the director of infectious diseases at the Zambia Ministry of Health, said that lenacapavir for PrEP has been rationed to certain sites and for people getting reinjection as the country awaits the arrival of 60,000 to 80,000 doses promised by the U.S. government. Byanyima said today that 20 million people will access long-acting prevention “if these breakthroughs are to change the course of the epidemic.”

In April 2026, the Global Fund to Fight AIDS, Tuberculosis and Malaria (the Global Fund) announced that it and the U.S. government were increasing their goal for lenacapavir PrEP by a million, from 2 to 3 million people, through 2028. In an interview with MHE, Mitchell Warren, executive director of AVAC, a U.S. advocacy group, credited the Global Fund and the U.S. government with pursuing a more ambitious program with lenacapavir than it had with other forms of PrEP. But Warren also said, "They kind of cheaped out.”

“We believe that we should be getting up to 5 million people a year within the next three to five years, and the sooner we get there, the faster this product drops even below the price of oral PrEP,” Warren said.

The PURPOSE trial results presented at the press conference last week did nothing to dampen the enthusiasm for lenacapavir for PrEP. According to the abstract presented by Kiwanuka, as participants in PURPOSE were finishing up the blinded phase of the trial on a rolling basis from July 8 to October 21, 2024, they were invited to participate in the open-label extension. Of the 4,417 participants eligible to join the open-label extension, 4,206 (95.2%) elected to start or continue with lenacapavir PrEP. There were no HIV infections among all participants on open-label lenacapavir.

during the first 52 weeks of open-label extension with over 4,493 person-years of follow-up, and one infection of a study participant who switched from blinded lenacapavir to oral daily emtricitabine/tenofovir disoproxil fumarate, which is sold under the brand name Truvada.

The PURPOSE 2 abstract presented by Losso told the same basic story. Almost all (99%) of those eligible to join the open-label extension went to their last visit during the blinded phase of the trial, and 95% decided to start lenacapavir or continue with it. One person became infected HIV during the open-label extension. Three people became infected during the blinded phase.