08:59 AM EDT, 10/28/2025 (MT Newswires) -- Merck ( MRK ) said Tuesday that its drug Welireg (belzutifan), paired with Eisai's Lenvima (lenvatinib), met the primary endpoint of progression-free survival in a phase 3 trial evaluating the dual regimen for patients with advanced renal cell carcinoma.

At an interim analysis, Welireg plus Lenvima demonstrated a "statistically significant and clinically meaningful" improvement in progression-free survival compared to cabozantinib, the companies said.

The drug combination also showed a statistically significant improvement in the secondary endpoint of objective response rate compared to cabozantinib, and a trend toward improvement in the other primary endpoint of overall survival was observed but did reach statistical significance at the time of the interim analysis, the companies said.

The safety profiles of the drugs were in line with previous studies and no new safety signals were observed, the companies said.