Mass General - Division of Clinical Research

include but are not limited to the following: - Male and female participants at least 12 years of age (at least 18 years of age for Cohort B1) - Diagnosis of one of the following: Advanced/metastatic pheochromocytoma/paraganglioma (PPGL), pancreatic neuroendocrine tumors (pNET), von Hippel-Lindau (VHL) disease associated localized tumors, or advanced wild-type gastrointestinal stromal tumor (wt GIST) or advanced solid tumors with Hypoxia Inducible Factor- 2 alpha subunit (HIF-2α) related genetic alterations - Cohort BI: VHL Disease-associated tumors: - Have a diagnosis of VHL disease as determined by a germline test locally and/or clinical diagnosis - Must be ≥18 years of age - Has a life expectancy of at least 3 months The main

include but are not limited to the following: - Unable to swallow orally administered medication or has a disorder that might affect the absorption of belzutifan - History of a second malignancy, unless potentially curative treatment has been completed with no evidence of malignancy for 2 years - Any of the following: A pulse oximeter reading <92% at rest, or requires intermittent supplemental oxygen, or requires chronic supplemental oxygen - Clinically significant cardiac disease, including unstable angina, acute myocardial infarction, or arterial bypass (CABG) or Percutaneous transluminal coronary angioplasty (PTCA) ≤6 months from study entry, or New York Heart Association Class III or IV congestive heart failure - Received prior treatment (except somatostatin analogs) with chemotherapy, targeted therapy, biologics, or other investigational therapy within the past 4 weeks of first dose of study intervention