Gilead and Merck report 48-week HIV results

• Gilead and Merck said their once-weekly oral HIV regimen maintained viral suppression in two Phase 3 trials.
• Gilead shares fell 1.2%, while Merck shares rose 0.8% during Tuesday trading.
• The companies said the results will support regulatory submissions for the investigational treatment.

Gilead Sciences (NASDAQ:GILD) and Merck (NYSE:MRK) said their once-weekly HIV pill maintained suppression through Week 48 in two Phase 3 trials.

ISLEND-1 recorded 0% above the viral-load threshold versus 0.3% with Biktarvy, while ISLEND-2 recorded 0.3% versus 1.3% with daily treatments.

“Long-acting therapies provide an alternative to daily pills,” said University Hospital Bonn Department of Medicine Professor Jürgen Rockstroh.

Treatment-related events were 13.5% versus 13.2% in ISLEND-1 and 18% versus below 1% in ISLEND-2, with no new safety concerns identified.

Following the announcement, Gilead's share price was down 1.2% at $131.64, while Merck was up 0.8% at $125.40.

The regimen combines Merck’s islatravir, which blocks reverse transcriptase, with Gilead’s lenacapavir, which disrupts HIV across several lifecycle stages.

The companies will present detailed results on July 29 at AIDS 2026 and said the data will support regulatory submissions.