Merck's Welireg (belzutifan) Approved in China for Locally Advanced Unresectable or Metastatic PPGL

Belzutifan (brand name Welireg/维利瑞) is a HIF-2α inhibitor whose U.S. approval was described in FDA documents as representing the approval of a drug that specifically targets this mechanism. On May 14, 2025, the FDA approved it for patients aged 12 and older with locally advanced, unresectable or metastatic pheochromocytoma or paraganglioma (PPGL), making it the only approved and available treatment in the U.S. for eligible patients with advanced PPGL, and the oral therapy approved for PPGL. Behind the PPGL indication, the registrational study NCT04924075 (MK-6482-015) is a Phase 2 trial planning to enroll 355 participants, with Objective Response Rate (ORR) assessed by BICR as primary endpoint, started August 12, 2021, currently recruiting, last updated October 21, 2026. Belzutifan was first approved in China in November 2024 for adult patients with VHL disease-associated tumors (per flcube.com, 需要核查).

On October 22, Merck announced that Welireg (belzutifan tablets) received approval in China for a new indication, for adolescent and adult patients aged 12 and older with locally advanced, unresectable or metastatic PPGL. This means the Chinese regulatory approval broadly aligns with the U.S. PPGL approval in May 2025; that U.S. indication was approved based on the efficacy and safety results of a Phase 2 trial（需要核查）.

From a commercialization standpoint, PPGL is a rare indication with a limited sales ceiling, but the product's value lies in its position of mechanistic exclusivity: the originator first occupies the approval pathway and pricing benchmark, so any future follower—regardless of whether a China-developed HIF-2α inhibitor emerges—must start from this approved pathway and from the future medical-insurance negotiation baseline. The clinical pipeline continues to advance: beyond the basket trial covering PPGL, Cambridge University Hospitals NHS Foundation Trust is running a Phase 2 study (NCT07680205) exploring belzutifan's impact on catecholamine metabolism, enrolling only 12 participants, started April 27, 2026, with tyrosine measurements as primary endpoint, suggesting the academic community is accumulating evidence at a finer mechanistic level（需要核查）.

Undisclosed information includes: the specific review pathway and supporting data details for this China approval, as well as pricing and reimbursement access arrangements, all to be confirmed; the development progress and head-to-head or bridging strategies of domestic HIF-2α inhibitors also have no public information. Future milestones include full data readout and label updates from NCT04924075, and market access negotiation progress in China.