AIDS 2026 Late-Breaker Wednesday July 29: Gilead-Merck ISLEND-1 and ISLEND-2 Detailed Week 48 Phase 3 Data for Investigational Once-Weekly Oral Single-Tablet Islatravir 2 mg / Lenacapavir 300 mg (ISL/LEN) Presented at Riocentro in Rio de Janeiro; Zero Percent of ISLEND-1 Participants and 0.3% of ISLEND-2 Participants Reached HIV-1 RNA at 50 Copies/mL or Higher, With Safety Profile Generally Similar to Comparator Daily Biktarvy and Standard-of-Care Regimens
Gilead Sciences (NASDAQ: GILD) and Merck (NYSE: MRK) presented detailed Phase 3 ISLEND-1 and ISLEND-2 Week 48 data during the late-breaking session at AIDS 2026 Wednesday July 29, 2026 in Rio de Janeiro. The investigational once-weekly oral single-tablet regimen of islatravir 2 mg / lenacapavir 300 mg (ISL/LEN) demonstrated non-inferior efficacy versus daily standard-of-care antiretroviral therapy in virologically-suppressed adults living with HIV who switched from daily Biktarvy (ISLEND-1) or other daily oral regimens (ISLEND-2). Primary endpoint results: 0% of ISLEND-1 participants on once-weekly ISL/LEN had HIV-1 RNA at 50 copies/mL or higher at Week 48 compared to 0.3% remaining on daily Biktarvy; in the open-label ISLEND-2 trial, 0.3% of participants on ISL/LEN had HIV-1 RNA at 50 copies/mL or higher versus 1.3% on daily standard-of-care regimens. Safety profile was generally similar to comparator regimens with no new safety signals identified. The Week 48 data will support planned regulatory submissions for the first once-weekly oral HIV treatment regimen. Lenacapavir is Gilead's first-in-class HIV capsid inhibitor; islatravir is Merck's nucleoside reverse transcriptase translocation inhibitor (NRTTI).