Once-weekly oral islatravir-lenacapavir is noninferior to daily HIV therapy
A phase 3 trial found that switching to once-weekly oral islatravir-lenacapavir (ISL/LEN) maintained HIV-1 suppression as effectively as daily bictegravir-emtricitabine-tenofovir alafenamide (B/F/TAF). The study met noninferiority criteria, with similar adverse event rates and no resistance to ISL/LEN. Gilead Sciences and Merck Sharp and Dohme funded the trial. The results apply only to those already virologically suppressed on B/F/TAF. Longer-term data is needed.
How this was made

The 30-second read
Why it matters
The trial met its non‑inferiority endpoint with comparable safety, suggesting a viable weekly HIV regimen.
Market read
Positive data may drive share price appreciation for GILD and MRK as investors anticipate a new product launch.
What to watch
Long‑term safety beyond 48 weeks and pricing strategy remain uncertain.
Background
Phase‑3 ISLEND‑1 trial compared weekly islatravir‑lenacapavir to daily B/F/TAF in virologically suppressed adults.
Ticker impact
Gilead Sciences co‑funded the phase‑3 ISLEND‑1 trial showing non‑inferior weekly regimen, indicating potential new product pipeline.
moderate upside as investors price in future launch potential
Phase‑3 success for a novel weekly HIV regimen reduces pill fatigue concerns and could capture market share.
Merck Sharp & Dohme co‑funded the ISLEND‑1 trial, supporting its antiviral portfolio with a new weekly regimen.
moderate upside as the market assesses future revenue from the regimen
Successful data adds a differentiated weekly option, enhancing Merck's infectious‑disease pipeline.
Market effects
Potential shift toward weekly HIV therapies could affect other antiretroviral developers.
US biotech investors may re‑price HIV treatment stocks globally.
Adds to the pipeline of long‑acting HIV treatments, a growing market segment.
Counterpoint
If adherence benefits are not proven in real‑world settings, the regimen may not translate to market share.
Key entities
- CompanyGilead Sciences
Co‑funded the trial and potential commercializer of the regimen.
- CompanyMerck Sharp & Dohme
Co‑funded the trial and potential commercial partner.




