The U.S. Food and Drug Administration (FDA) approved Welireg (belzutifan) for patients ages 12 years and older with locally advanced, unresectable or metastatic pheochromocytoma or paraganglioma.
Pheochromocytoma and paraganglioma are rare tumors that develop from similar tissue. Pheochromocytoma form in the center of the adrenal gland, whereas paraganglioma form outside the adrenal gland in nerve tissue near certain blood vessels and nerves. Symptoms are often linked to excess catecholamine production causing sustained or paroxysmal elevations in blood pressure, headache, episodic profuse sweating, palpitations, pallor and apprehension or anxiety. The rare condition tends to present at younger ages, to be multifocal, bilateral, and recurrent, or to have multiple synchronous neoplasms.
Belzutifan is a hypoxia-inducible factor 2 alpha (HIF-2α) inhibitor and the first oral therapy to be approved by the FDA for pheochromocytoma or paraganglioma. The approval follows positive data from the LITESPARK-015 study, a phase 2, open-label, multi-cohort clinical trial evaluating the safety and efficacy of belzutifan.
Cohort A1 consisted of 72 patients with measurable disease as verified by blinded independent central review (BICR) using RECIST v1.1. The primary efficacy endpoint measure was objective response rate by BICR using RESIST v1.1, which was 26% following treatment with belzutifan. Additionally, duration of response was 20.4 months and of 60 patients on baseline antihypertensive medications, 19 had a reduction in at least one medication by at least 50% for at least six months.
The most common adverse events included anemia, fatigue, musculoskeletal pain, decreased lymphocytes, increased alanine aminotransferase, increased aspartate aminotransferase, increased calcium dyspnea, increased potassium, decreased leukocytes, headache, increased alkaline phosphatase, dizziness, and nausea.
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To learn more about PPGL and other rare genetic conditions, visit https://checkrare.com/diseases/congenital-and-genetic-conditions/