FDA backs Merck’s dual-pronged push in kidney cancer with Welireg–Keytruda combo approval

The US Food and Drug Administration (FDA) has approved a combination regimen of Merck & Co.’s Keytruda (pembrolizumab) and Welireg (belzutifan) for the adjuvant treatment of adults with clear cell renal cell carcinoma (ccRCC) at risk of recurrence following surgery.

The decision also extends to Keytruda Qlex, a subcutaneous formulation of the anti–PD-1 therapy (pembrolizumab/berahyaluronidase alfa-pmph), marking another step in Merck’s strategy to broaden Keytruda’s delivery formats and lifecycle.

Phase III data underpinning approval

The approval follows a priority review and is based on the Phase III LITESPARK-022 trial, which enrolled 1,841 patients who had undergone nephrectomy and were classified as intermediate-high or high risk of recurrence, or had resected metastatic disease with no evidence of active cancer.

Patients were randomised to receive either Welireg plus Keytruda or Keytruda plus placebo in the adjuvant setting.

At a prespecified interim analysis, the combination demonstrated a 28% improvement in disease-free survival (DFS), defined as time to recurrence, metastasis or death. There were 186 DFS events in the combination arm compared with 246 in the control group. Median DFS was not reached in either arm, and overall survival data remain immature.

Expanding Welireg’s role in renal cell carcinoma

Welireg (belzutifan), a HIF-2α inhibitor, already carries an indication in kidney cancer following its 2023 approval for previously treated advanced renal cell carcinoma patients who had received PD-(L)1 and VEGF-targeted therapies.

The latest approval moves the therapy further upstream into the post-surgical adjuvant setting, reinforcing Merck’s intent to build a multi-line renal cancer franchise spanning both immunotherapy and targeted hypoxia pathways.

Keytruda’s growing footprint in kidney cancer

This marks Keytruda’s fourth approved indication in renal cell carcinoma.

Earlier approvals include first-line advanced settings in combination with Pfizer’s Inlyta (axitinib) and Eisai’s Lenvima (lenvatinib), as well as a post-nephrectomy indication based on the KEYNOTE-564 study, where Keytruda demonstrated a 38% improvement in overall survival in high-risk patients.

Taken together, these approvals consolidate Keytruda as a central backbone therapy across multiple stages of kidney cancer treatment.

Competitive backdrop remains unresolved

Despite the expanding evidence base for Keytruda-based combinations, treatment selection in renal cell carcinoma remains highly competitive.

Some clinical experts continue to favour Bristol Myers Squibb’s Opdivo (nivolumab)-based combinations, citing ongoing uncertainty around optimal sequencing and long-term comparative outcomes across immuno-oncology regimens.

This leaves the field open, with multiple checkpoint inhibitor combinations still competing for long-term dominance in both advanced and adjuvant kidney cancer settings.

Outlook

The Welireg–Keytruda approval strengthens Merck’s position in renal oncology by combining immunotherapy with targeted hypoxia biology in a high-risk post-surgical population.

While the immediate clinical impact will depend on uptake and sequencing preferences, the broader strategic signal is clear: Merck is continuing to build depth across multiple mechanisms in kidney cancer rather than relying on single-agent dominance.

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