Belzutifan Efficacy and Tolerability in Patients with Sporadic Metastatic Clear Cell Renal Cell Carcinoma.

Background And Objective: Belzutifan, a hypoxia-inducible factor 2 alpha inhibitor, was approved initially for patients with von Hippel-Lindau disease and more recently for sporadic, metastatic clear cell renal cell carcinoma (ccRCC) based on the results of LITESPARK-005. There is a paucity of data regarding real-world experience with belzutifan in patients with sporadic, metastatic ccRCC. This study aims to describe clinical outcomes with belzutifan in patients with sporadic, metastatic ccRCC.

Methods: A retrospective study of 22 patients who received belzutifan at MD Anderson Cancer Center prior to the Food and Drug Administration approval was conducted. Progression-free survival (PFS) and objective response rate (ORR) were assessed by a blinded radiologist using Response Evaluation Criteria In Solid Tumors (RECIST) version 1.1. PFS and overall survival (OS) were measured from belzutifan initiation.

Key Findings And Limitations: The median follow-up time was 14.9 mo. Most patients had International Metastatic RCC Database Consortium intermediate-risk disease, more than three metastatic sites, and a median of five prior lines of treatment at initiation of belzutifan; all patients received prior immune checkpoint therapy (ICT) and vascular endothelial growth factor receptor tyrosine kinase inhibitors (VEGFR-TKIs). The median PFS was 8.51 mo (95% confidence interval [CI] 0-18.4) and ORR was 36.4%. The median OS was 14.72 mo (95% CI 7.34-22.10). Of 22 patients, four (18.2%) patients required dose reductions and three (13.6%) patients discontinued belzutifan because of adverse drug events (ADEs). The most common ADEs were anemia (77.3%; 17/22) and hypoxia (36.4%; 8/22). There were no treatment-related deaths.

Conclusions And Clinical Implications: In a heavily pretreated cohort of patients with sporadic, metastatic ccRCC, belzutifan had meaningful clinical activity and was well tolerated. These real-world results add to the results of LITESPARK-005 and support the use of belzutifan after progression on ICT and VEGFR-TKIs.

Patient Summary: Belzutifan is a new medicine used to treat a type of clear cell kidney cancer that has spread to other parts of the body (metastasized). A study at MD Anderson Cancer Center followed 22 patients who were treated with belzutifan, and found that it worked to control the cancer for almost 9 mo and caused the cancer to shrink in 36% of patients. This study confirms that belzutifan can be effective and safe, even after other treatments have not worked.