Once-Weekly HIV Pill Matches Daily Therapy in Phase 3 Trials

A once-weekly oral pill for HIV held its own against daily standard-of-care therapy in two phase 3 trials, according to results presented July 29 at the 26th International AIDS Conference in Rio de Janeiro and published simultaneously in the New England Journal of Medicine.

The trials, called ISLEND-1 and ISLEND-2, tested a single tablet combining islatravir, developed by Merck, and lenacapavir, developed by Gilead Sciences. According to a joint announcement reviewed from Gilead Sciences' investor relations site, the primary endpoint results at week 48 showed the weekly regimen was effective in adults already virologically suppressed who switched from Biktarvy, the current guideline-preferred daily pill, or other standard oral daily regimens.

The numbers are hard to dismiss. In the ISLEND-1 arm, none of the 304 participants on the weekly pill developed a viral load of 50 copies per milliliter or higher at week 48, compared with one participant in the 303-person daily-pill comparison group, according to data reported by Managed Healthcare Executive from the conference. More than 93 percent of participants in both groups maintained viral suppression overall, and no new safety concerns were identified.

The studies will run to 96 weeks, so this is an interim read. That matters. Virologic suppression at 48 weeks is a meaningful bar, but HIV treatment trials are watched closely for late failures and resistance patterns. Regulators will want the full two-year picture before approving any label claim.

The patient population is worth naming clearly. According to aidsmap's conference coverage, the median age in ISLEND-1 was approximately 49 years, with half of participants older than 50 and 17 percent older than 65. The ISLEND-1 trial itself enrolled 607 adults across 106 clinical sites in 12 countries, according to reporting by MedicalXpress. That's a reasonably broad sample, though the studies enrolled adults who were already suppressed on a stable regimen, meaning people who were adherent to begin with. That's a different population than someone struggling with a daily pill schedule, which is precisely the group a weekly option is meant to help most.

Professor Jürgen Rockstroh, head of the HIV Outpatient Clinic at University Hospital Bonn and lead presenter on ISLEND-1, was quoted in aidsmap's coverage saying the data show the pill's potential as "the first once-weekly oral single-tablet treatment option." Dr. Amy Colson of the Community Resource Initiative in Boston and Cambridge Health Alliance presented the ISLEND-2 findings at the same session.

According to the joint Gilead and Merck regulatory statement, these data will form the basis of regulatory submissions. That puts an FDA filing on the horizon, though no timeline was announced.

The access question hasn't been answered. Lenacapavir already carries a high list price in its injectable prevention form, and affordability advocates have been vocal about that. Managed Healthcare Executive noted that questions about price and access hung over the otherwise positive conference moment. That conversation is going to matter enormously for whether a weekly pill actually reduces adherence burden for the people most likely to benefit, or whether it becomes another option only accessible to patients with good insurance.

From a clinical standpoint, a weekly oral pill sits in a useful middle ground: more convenient than daily therapy, less invasive than the long-acting injectable regimens that require clinic visits. Whether it earns a place in guidelines will depend on the full 96-week data, the regulatory review, and ultimately what it costs to dispense.

Sources cited:
- Gilead Sciences Investor Relations (https://investors.gilead.com/news/news-details/2026/Investigational-Once-Weekly-Oral-HIV-Treatment-Regimen-of-Islatravir-and-Lenacapavir-Maintained-Virological-Suppression-in-Adults-With-HIV-Who-Switched-Antiretroviral-Therapy/default.aspx)
- Managed Healthcare Executive (https://www.managedhealthcareexecutive.com/view/promising-results-for-a-once-weekly-hiv-treatment-pill-are-reported-aids-2026)
- aidsmap (https://www.aidsmap.com/news/jul-2026/once-weekly-islatravir-lenacapavir-combination-pill-maintains-hiv-viral-suppression)
- MedicalXpress (https://medicalxpress.com/news/2026-07-international-weekly-hiv-pill-daily.html)
- New England Journal of Medicine (via MedicalXpress citation) (https://medicalxpress.com/news/2026-07-international-weekly-hiv-pill-daily.html)