By Michael Gwarisa
A once-weekly pill for HIV treatment has performed as well as standard daily therapy in two landmark Phase III clinical trials, bringing researchers a step closer to offering people living with HIV the world’s first complete once-weekly oral treatment regimen.
The findings from the ISLEND-1 and ISLEND-2 studies will be presented at the 26th International AIDS Conference (AIDS 2026) in Rio de Janeiro, where scientists say the investigational combination of islatravir and lenacapavir could transform HIV treatment by reducing the burden of taking medication every day while maintaining viral suppression.
If approved by regulators, the investigational regimen combining islatravir and lenacapavir could provide a new treatment option for millions of adults living with HIV who have already achieved viral suppression but struggle with the demands of taking medication every day.
Announcing the results during a pre-conference scientific briefing, Kenneth Ngure, President-elect of the International AIDS Society (IAS) and Associate Professor of Global Health at Jomo Kenyatta University of Agriculture and Technology in Kenya, said the development represents a significant step toward giving people living with HIV more flexibility in managing their treatment.
“While once-daily single-tablet regimens have transformed the outlook for millions of people living with HIV, daily pill fatigue and adherence challenges remain,” Ngure said.
“Many people with HIV want the freedom of a long-acting option, but injectable medications come with strict scheduling requirements.”
He said the once-weekly tablet has the potential to bridge the gap between daily oral therapy and long-acting injectable medicines.
“Treatment needs to fit into people’s lives, not the other way around,” Ngure said.
“People living with HIV need new treatment options that offer flexibility, and a weekly pill could broaden the choices available for adults with virological suppression. We are excited to share these results at AIDS 2026.”
The encouraging findings follow positive topline results announced last month by Gilead Sciences and Merck (MSD outside the United States and Canada), the companies jointly developing the regimen. Both companies have indicated they intend to submit the data to regulatory authorities around the world.
The ISLEND-1 trial enrolled adults living with HIV whose virus had already been suppressed while taking the widely prescribed once-daily regimen bictegravir/emtricitabine/tenofovir alafenamide, commonly marketed as Biktarvy.
Participants were randomly assigned either to switch to the once-weekly islatravir-lenacapavir tablet or remain on their daily treatment.
The study demonstrated that the weekly regimen was statistically non-inferior to Biktarvy, meaning it maintained viral suppression just as effectively while also being well tolerated by participants.
The findings will be presented at AIDS 2026 by Professor Jürgen Rockstroh of University Hospital Bonn, who led the ISLEND-1 study.
The second Phase III trial, ISLEND-2, evaluated adults with virologically suppressed HIV receiving a variety of standard daily oral antiretroviral regimens. Participants were similarly randomised to either continue their existing daily medication or switch to the once-weekly tablet. Like the first trial, the once-weekly regimen proved to be efficacious, well tolerated and statistically non-inferior to existing daily therapies.
The ISLEND-2 results will be presented by Dr Amy Colson of the Community Resource Initiative and the Zinberg Clinic at Cambridge Health Alliance in the United States.
Together, the two international studies provide vidence to date that a once-weekly oral regimen could maintain viral suppression without sacrificing effectiveness or safety.
For decades, HIV treatment has steadily evolved from complicated multi-pill combinations taken several times a day to highly effective once-daily single-tablet regimens. More recently, long-acting injectable medicines administered every one or two months have expanded treatment choices for some patients.
However, injectable treatment requires clinic appointments and strict adherence to dosing schedules, creating logistical challenges for some people.
A once-weekly oral pill could offer many of the convenience benefits associated with long-acting treatment while allowing patients to avoid regular injections and frequent clinic visits.
Researchers say reducing treatment burden remains a critical priority, particularly for people who experience pill fatigue after years of lifelong therapy. Maintaining consistent adherence is essential for keeping the virus suppressed, protecting the immune system and preventing HIV transmission. Missing doses over time can increase the risk of treatment failure and, in some cases, the development of drug resistance.
The once-weekly regimen is therefore being viewed as a potential advance not because current medicines are ineffective, but because expanding treatment options allows care to be tailored to individual preferences and lifestyles. The studies are expected to generate considerable discussion among HIV clinicians and policymakers attending AIDS 2026 as experts consider where a weekly oral regimen could fit within future HIV treatment guidelines.
The conference itself is taking place against the backdrop of growing concern over reductions in global HIV funding, even as scientific breakthroughs continue to emerge.
Opening the media briefing, Tara Mansell, Head of Communications at the International AIDS Society, described the current moment as one of the most challenging periods in the global HIV response.
“It takes place amid a severe funding crisis, where HIV programmes in some of the most affected countries are being drastically cut back,” she said.
Despite those challenges, she noted that researchers continue to make remarkable progress.
“Despite these shifting geopolitical sands, we have incredible scientific advances within our grasp.”
Among those advances, many scientists believe the once-weekly islatravir-lenacapavir regimen could become one of the defining treatment breakthroughs presented at AIDS 2026.
