The National Medical Products Administration (NMPA) in China has granted approval to MSD's Welireg (belzutifan), an oral hypoxia-inducible factor-2 alpha (HIF-2α) inhibitor, for the treatment of adult patients with specific types of von Hippel-Lindau (VHL) disease-associated tumors. This approval marks a significant advancement for patients with renal cell carcinoma (RCC), central nervous system (CNS) hemangioblastomas, or pancreatic neuroendocrine tumors (pNET) who do not require immediate surgery.
The approval is grounded in the outcomes of the Phase II LITESPARK-004 trial, which assessed objective response rate (ORR) and median duration of response (DOR). This marks the 17th global approval for Welireg for this indication, following its initial approval in the US in August 2021 for similar uses.
LITESPARK-004 Trial Results
The open-label LITESPARK-004 trial involved 61 participants with VHL-associated RCC. The results showed an ORR of 49%, with all responses being partial responses. The median DOR was not reached, with ongoing responses spanning from 2.8 to over 22 months.
Significant response rates were also observed in patients with other VHL-associated tumors. For CNS hemangioblastomas, the ORR was 63%, comprising a 4% complete response rate and a 58% partial response rate. Patients with VHL-associated pNET demonstrated an ORR of 83%, including a 17% complete response rate and a 67% partial response rate.
Expert Commentary
Dr. Marjorie Green, head of oncology, global clinical development, and senior vice-president at MSD research laboratories, emphasized the importance of this approval, stating, "This approval of WELIREG brings the first and only systemic therapy to adult patients in China with certain VHL disease-associated tumours who, to date, have not had access to a non-surgical treatment option to help manage manifestations of VHL disease."
Previous Approvals and Ongoing Research
Welireg has previously been approved in the US for treating adult patients with advanced RCC following treatment with a programmed death receptor-1 (PD-1) or programmed death-ligand 1 (PD-L1) inhibitor and a vascular endothelial growth factor-tyrosine kinase inhibitor (VEGF-TKI), based on the Phase III LITESPARK-005 trial results.
MSD is continuing to investigate Welireg in advanced RCC and other tumor types through a comprehensive clinical development program, including Phase II and III trials, both as a monotherapy and in combination with other drugs.
