The Food and Drug Administration approved belzutifan (Welireg) in combination with pembrolizumab (Keytruda) today as adjuvant therapy for adults with clear-cell renal cell carcinoma at high risk of recurrence following nephrectomy, marking the first approval of a HIF-2α inhibitor in any post-surgical cancer setting.

The approval is based on LITESPARK-022 (NCT05239728), a randomised, double-blind, placebo-controlled Phase 3 trial in which patients who had undergone nephrectomy for high-risk ccRCC were randomised to belzutifan plus pembrolizumab or placebo plus pembrolizumab. The primary endpoint was disease-free survival. The combination produced a statistically significant DFS improvement: hazard ratio 0.72 (95% CI 0.59–0.87), a 28% reduction in the risk of recurrence or death compared with pembrolizumab plus placebo.

Belzutifan, a selective oral HIF-2α inhibitor, was first approved in 2021 for adults with von Hippel-Lindau disease-associated tumours. In clear-cell RCC, loss of the VHL tumour suppressor gene leads to constitutive HIF-2α activity, driving expression of VEGF, erythropoietin, and other factors that fuel tumour growth and immune evasion. By inhibiting HIF-2α directly, belzutifan targets the disease’s primary transcriptional driver rather than its downstream effectors.

Pembrolizumab, a PD-1 checkpoint inhibitor, received its own adjuvant RCC approval in August 2022 based on KEYNOTE-564 (DFS HR 0.68). Adding belzutifan to that established backbone appears to confer additional recurrence reduction, though no head-to-head trial versus adjuvant pembrolizumab monotherapy has been conducted and absolute benefit magnitude will require longer follow-up and patient-level analysis.

High-risk criteria in LITESPARK-022 included pT2 disease with Grade 4 or sarcomatoid differentiation; pT3a or higher; regional lymph node involvement (pN+); or M1 disease rendered no evidence of disease by prior complete resection. Common adverse events included anaemia and fatigue, consistent with prior belzutifan experience, plus immune-mediated events at rates expected for pembrolizumab.

The approval extends the therapeutic arc of belzutifan, which also holds approval in the metastatic ccRCC setting in combination with lenvatinib (LITESPARK-023). Merck’s HIF-2α programme now spans the full treatment continuum — adjuvant, first-line metastatic, and subsequent lines — a breadth not previously achieved with a single targeted agent in kidney cancer.