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

July 20, 2026: Gilead Sciences, Inc. (NASDAQ: GILD) and Merck (NYSE: MRK) announced that detailed Week 48 outcomes from the Phase 3 ISLEND-1 (NCT06630286) and ISLEND-2 (NCT06630299) trials of investigational once-weekly oral islatravir 2 mg/lenacapavir 300 mg (ISL/LEN) will be presented for the first time at the 26th International AIDS Conference (AIDS 2026). Late-breaking presentations are scheduled for Wednesday, July 29, with inclusion in the AIDS 2026 press program on Tuesday, July 21. The companies said these data will form the basis of regulatory submissions.

ISLEND-1 (switch from BIKTARVY): At Week 48, ISL/LEN was noninferior to BIKTARVY for maintaining virologic suppression; 0% on ISL/LEN vs 0.3% on BIKTARVY had HIV-1 RNA ≥50 copies/mL (FDA snapshot). Treatment-related AEs were similar (13.5% vs 13.2%); serious AEs 5.3% vs 4.6%; discontinuations due to AEs 2% vs 1.7%.

ISLEND-2 (switch from other daily oral SOC): At Week 48, ISL/LEN was noninferior; 0.3% vs 1.3% had HIV-1 RNA ≥50 copies/mL. Treatment-related AEs were 18% with ISL/LEN and <1% with SOC; discontinuations due to AEs were 1% vs <1%. Patient-reported outcomes favored ISL/LEN (higher satisfaction, lower treatment burden).