Merck, Gilead Serve ‘Sweet and Sour’ Spread After HIV Win, Cancer Stumble

Why It Matters

The HIV data may secure a differentiated, adherence‑friendly therapy that strengthens Gilead’s market lead, whereas the NSCLC failure curtails a potential growth engine for both companies’ oncology portfolios.

Key Takeaways

• IS/LEN pill matched Biktarvy in 48‑week suppression
• Trial shows first long‑acting oral HIV regimen possibility
• Trodelvy/Keytruda combo missed statistical significance in NSCLC
• Discontinuation ends KEYNOTE‑D46, limiting future oncology revenue
• Gilead’s 2025 sales hit $1.4 billion despite setbacks

Pulse Analysis

The HIV treatment landscape is shifting toward regimens that simplify dosing and improve adherence. A once‑weekly oral pill that delivers the same viral suppression as daily therapies addresses a long‑standing patient need for convenience, especially among those who struggle with daily pill burden. Gilead’s Biktarvy has dominated the market, but the islatravir‑lenacapavir combination could carve out a niche as the first long‑acting oral option, potentially expanding the total addressable market and reinforcing Gilead’s reputation as an innovator in antiretroviral therapy.

Results from the ISLEND‑1 and ISLEND‑2 Phase 3 studies showed non‑inferiority to Biktarvy and other standard‑of‑care regimens at 48 weeks, a key efficacy benchmark for regulators. The data, while not yet publicly detailed, are slated for presentation at an upcoming medical congress and subsequent filing with health authorities worldwide. If approved, the pill could be positioned for patients seeking less frequent dosing, giving Merck a foothold in HIV and allowing Gilead to diversify its portfolio beyond daily tablets. Competitors will need to respond, as the convenience factor may become a decisive differentiator in a crowded market.

Conversely, the termination of the KEYNOTE‑D46 trial underscores the challenges of extending Trodelvy’s oncology reach. Despite a 6% growth to $1.4 billion in 2025, Trodelvy has stumbled in multiple NSCLC studies, failing to demonstrate overall‑survival benefits. The lack of statistical significance in progression‑free survival against Keytruda monotherapy led the data safety board to recommend discontinuation, dampening expectations for a first‑line indication that could have accelerated revenue growth. This setback forces both Merck and Gilead to reassess their lung‑cancer strategies, potentially redirecting resources toward more promising pipelines or combination approaches, while investors watch closely for the impact on future earnings guidance.