Welireg (belzutifan) was the first HIF-2 alpha inhibitor approved, targeting the pathway unleashed when von Hippel-Lindau function is lost and tumors begin forming across multiple organs.
By blocking HIF-2 alpha, the transcription factor that accumulates when VHL function is lost, Welireg interrupts the signal driving tumor formation. The once-daily tablet treats adults with von Hippel-Lindau disease who require therapy for associated renal cell carcinoma, central nervous system hemangioblastomas, or pancreatic neuroendocrine tumors not needing immediate surgery.
Welireg has since expanded into advanced sporadic renal cell carcinoma after immunotherapy and TKI treatment, greatly widening its addressable population. With orphan designation, first-in-class status, and no generic competition, it is the benchmark HIF-2 alpha asset.
