Gilead, Merck weekly HIV pill suppresses virus in late-stage trials

• In the first trial, 0% of patients on the weekly pill had detectable viral levels at 48 weeks versus 0.3% on daily Biktarvy; in the second trial, 0.3% on weekly treatment had detectable levels versus 1.3% on standard daily regimens
• Side effects were similar to daily treatments with no new safety concerns identified, most commonly including headache, nausea, and diarrhea
• The development is critical for Gilead's HIV franchise as it seeks to strengthen its portfolio alongside blockbuster drug Biktarvy, with lenacapavir (branded Yeztugo) approved in 2023

Summary:

Gilead Sciences and Merck announced positive results from two late-stage trials for their experimental once-weekly HIV pill, potentially marking the first weekly treatment regimen for the disease. The single-tablet combination uses Merck's islatravir and Gilead's lenacapavir (branded as Yeztugo, approved in 2023).

Key Trial Results:

• First trial: 0% of patients on the weekly pill had detectable viral levels at 48 weeks, compared to 0.3% on Gilead's daily Biktarvy
• Second trial: 0.3% on the weekly treatment had detectable HIV levels versus 1.3% on standard daily regimens
• The weekly treatment proved non-inferior to existing daily therapies, meeting the studies' primary endpoints

Safety Profile:

Side effects were comparable to daily treatments, with no new safety concerns identified. Common side effects included headache, nausea, and diarrhea.

Market Implications:

The results support regulatory filings for what could become the first once-weekly HIV treatment, representing a significant advancement in patient convenience. Investors are closely monitoring lenacapavir's rollout as Gilead seeks to strengthen its HIV franchise alongside blockbuster drug Biktarvy. This development could reshape the HIV treatment market by reducing the burden of daily medication adherence.

The announcement follows Merck's recent FDA approval in April for Idvynso, another once-daily HIV pill combination, demonstrating continued innovation in the HIV treatment space by both pharmaceutical companies.