Islatravir (MK-8591D) and Lenacapavir - (ISLEND)

July 15, 2026: Merck (NYSE: MRK) announced upcoming HIV treatment and prevention pipeline data presentations at the 26th International AIDS Conference (AIDS 2026) in Rio de Janeiro (July 26–31, 2026), including multiple late-breaker abstracts focused on investigational once-weekly oral regimens for virologically suppressed HIV-1.

Islatravir/lenacapavir (ISL/LEN): Late-breaker oral presentations will report Week 48 primary efficacy and safety results from the pivotal Phase 3 switch trials ISLEND-1 (vs continuing bictegravir/emtricitabine/tenofovir alafenamide) and ISLEND-2 (vs continuing daily standard of care). Presentations are scheduled July 29, 2026 (10:30–11:30 and 15:00–16:00 BRT).

Islatravir + ulonivirine (ISL+ULO): Late-breaker Week 24 primary efficacy and safety results from the Phase 2b MK-8591B-060 switch study (vs continuing BIC/FTC/TAF) will be presented July 29, 2026 (15:00–16:00 BRT).

Doravirine/islatravir (DOR/ISL): An oral presentation reports that once-daily DOR/ISL (100/0.25 mg) maintained viral suppression at Week 96 in participants with baseline NNRTI resistance-associated mutations and/or M184I/V (July 28, 2026), alongside additional Phase 3/Phase 1 posters.

Prevention (MK-8527/alimatravir): Phase 3 PrEP trials EXPrESSIVE-10 and EXPrESSIVE-11 are enrolling; additional Phase 1 and resistance-related posters are listed.

Merck will host HIV policy/medical symposia July 29, 2026, and a virtual HIV Investor Event on Aug. 3, 2026.