Belzutifan/MK-6482 for the Treatment of Advanced Pheochromocytoma/Paraganglioma (PPGL), Pancreatic Neuroendocrine Tumor (pNET), Von Hippel-Lindau (VHL) Disease-Associated Tumors, Advanced Gastrointestinal Stromal Tumor (wt GIST), or Solid Tumors With HIF-2α Related Genetic Alterations (MK-6482-015)

The main inclusion criteria 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 exclusion criteria 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 conge…