Merck’s combination of Welireg and Keytruda failed to deliver a significant improvement in newly diagnosed patients with advanced kidney cancer, the company announced.
The Phase 3 trial tested belzutifan (Welireg) on top of pembrolizumab (Keytruda) in treatment-naive patients with advanced disease. The goal: show that adding Welireg to an existing Keytruda regimen would push outcomes beyond what Keytruda alone achieves. The trial data didn’t support it.
The commercial consequence is direct. Welireg holds FDA clearance in kidney cancer, but in a narrower patient population than first-line advanced disease would represent. A positive Phase 3 read here would have opened the drug to a far larger pool of eligible patients and the corresponding revenue upside. That path is now closed.
First-line advanced kidney cancer is one of oncology’s most competitive indications. Merck built this Phase 3 program on the belief that Welireg could extend the company’s kidney cancer position beyond what Keytruda alone controls. The data said no, and the company’s Welireg franchise stays constrained to its current scope.
Merck hasn’t detailed next steps for the Welireg program following the Phase 3 miss.
— Sarah Chen