Merck's WELIREG® Gains Priority FDA Review for Rare Tumors

Merck, known as MSD outside the U.S. and Canada, has announced that the U.S. Food and Drug Administration (FDA) has accepted a supplemental new drug application (sNDA) for WELIREG® (belzutifan). The sNDA seeks approval to treat adults and children (12 and older) with advanced or metastatic pheochromocytoma and paraganglioma (PPGL), rare tumors with no current approved therapies in the U.S. The FDA has granted priority review status, setting a decision deadline under the Prescription Drug User Fee Act (PDUFA) for May 26, 2025.

The submission is based on promising data from the Phase 2 LITESPARK-015 trial, which evaluated objective response rate (ORR) and duration of response (DOR). Dr. Marjorie Green, head of oncology at Merck Research Laboratories, emphasized the company’s dedication to addressing unmet needs in rare cancers, highlighting WELIREG’s potential to fill a critical treatment gap. Already approved for von Hippel-Lindau disease-associated tumors and advanced renal cell carcinoma, WELIREG continues to be explored in Phase 2 and 3 trials for other oncologic conditions.