The Promises of Belzutifan
- Belzutifan, a hypoxia-inducible factor-2 alpha (HIF-2α) inhibitor, has demonstrated significant antitumor activity across several rare and refractory cancer types, including advanced paraganglioma, Von Hippel-Lindau (VHL) disease and clear-cell...
- The medication targets the HIF regulatory pathway, which plays a critical role in the pathophysiology of certain tumors and their ability to progress and metastasize.
- Data from the LITESPARK-015 open-label, multicohort phase 2 trial indicate that belzutifan achieves durable antitumor activity in patients with advanced paraganglioma.
Belzutifan, a hypoxia-inducible factor-2 alpha (HIF-2α) inhibitor, has demonstrated significant antitumor activity across several rare and refractory cancer types, including advanced paraganglioma, Von Hippel-Lindau (VHL) disease and clear-cell kidney cancer.
The medication targets the HIF regulatory pathway, which plays a critical role in the pathophysiology of certain tumors and their ability to progress and metastasize.
Treatment of Advanced Paraganglioma
Data from the LITESPARK-015 open-label, multicohort phase 2 trial indicate that belzutifan achieves durable antitumor activity in patients with advanced paraganglioma. Paragangliomas are rare neuroendocrine tumors that are typically slow-growing, though approximately 55% of patients eventually develop metastasis.
In a cohort 1A study from the trial, follow-up data at a median of 30.2 months showed an objective response rate (ORR) of 26.4%. The median duration of response (DOR) was 20.4 months.
These findings were presented at the 2025 European Society for Medical Oncology (ESMO) Annual Congress, held from October 17 to October 21, 2025, in Berlin. The results supported the fast-track approval by the U.S. Food and Drug Administration (FDA) for eligible patients with advanced, unresectable, or metastatic pheochromocytoma or paraganglioma.
The safety profile observed in this population was consistent with previous trials, with adverse events described as manageable.
Applications in VHL Disease and Kidney Cancer
Beyond neuroendocrine tumors, belzutifan has shown promise in treating advanced Von Hippel-Lindau (VHL) disease. Reports from November 10, 2025, indicate that the drug provides manageable safety and promising disease control, including notable tumor responses, although anemia was noted as a side effect.
The drug has also been evaluated for refractory clear-cell renal cell carcinoma (kidney cancer). In a phase 3 clinical trial, belzutifan demonstrated superior progression-free survival compared to everolimus, an mTOR inhibitor used as a standard targeted therapy for refractory kidney cancer.
Patients treated with belzutifan in the kidney cancer trial also experienced a higher objective response rate. The medication received FDA approval on December 14, 2023, for this indication.
Mechanism of Action and Clinical Significance
The efficacy of belzutifan is rooted in its ability to inhibit HIF-2α. Molecular characterization of paragangliomas has revealed that HIF-2α is critical for cancer progression and metastasis, making it a viable therapeutic target for precision oncology.
For patients with refractory clear-cell kidney cancer, the introduction of this drug represents a shift in treatment options. Many patients in this category exhaust existing immunotherapies and targeted therapies, leaving them with limited alternatives.
Moshe Ornstein, MD, MA, medical oncologist at Cleveland Clinic
It’s been many years since a therapy with a novel mechanism of action has been developed in kidney cancer.