US pharmaceutical company Merck & Co Inc (NYSE:MRK), known as MSD outside the US and Canada, and its Japanese partner Eisai Co Ltd (TYO:4523) announced on Friday that the US Food and Drug Administration (FDA) has approved WELIREG (belzutifan) plus LENVIMA (lenvatinib) for adults with advanced renal cell carcinoma with a clear cell component (ccRCC) following treatment with a PD-1 or PD-L1 inhibitor.

This approval is based on the Phase 3 LITESPARK-011 trial, where the combination delivered a statistically significant improvement in progression-free survival versus cabozantinib, reducing the risk of disease progression or death by 26%.

Median progression-free survival was 14.6 months with WELIREG plus LENVIMA, compared with 10.6 months with cabozantinib. The combination also produced a statistically significant objective response rate of 53%, compared with 40% for cabozantinib.

At the final analysis, overall survival did not reach statistical significance for WELIREG plus LENVIMA versus cabozantinib.

Merck and Eisai said the results will be presented at the European Society for Medical Oncology Congress 2026 in Madrid, Spain.

The companies said WELIREG plus LENVIMA is the first approved combination of a HIF-2 alpha inhibitor and a multi-targeted VEGFR tyrosine kinase inhibitor for this patient population.