Global pharma powerhouse Merck has unveiled striking new data from its pivotal Phase 3 LITESPARK-022 trial, showing that the combination of KEYTRUDA (pembrolizumab) and WELIREG (belzutifan) significantly improves outcomes for patients with clear cell renal cell carcinoma (RCC) after nephrectomy.

At a median follow-up of 28.4 months, KEYTRUDA plus WELIREG reduced the risk of disease recurrence or death by 28% compared to KEYTRUDA plus placebo. Median disease-free survival (DFS) was not reached in either arm, with an estimated 24-month DFS rate of 80.7% for the combination versus 73.7% for KEYTRUDA alone. The trial will continue to evaluate overall survival, a key secondary endpoint.

“Approximately 40% of patients with renal cell cancer may experience tumor growth after initial treatment. Results from LITESPARK-022 mark an important step forward for certain patients with renal cell cancer, showing a significant reduction in the risk of disease recurrence or death compared to pembrolizumab alone,” said Dr. Toni K. Choueiri, director of the Lank Center for Genitourinary Oncology at Dana-Farber Cancer Institute.

“The combination of pembrolizumab and belzutifan is the first ever regimen in the adjuvant setting for renal cell cancer to demonstrate an improvement in disease-free survival over pembrolizumab monotherapy, positioning this regimen to potentially reshape clinical practice.”

Merck emphasized the broader significance of the findings. “LITESPARK-022 is a critical part of our comprehensive RCC clinical development program, and the Phase 3 results presented at ASCO GU underscore the importance of KEYTRUDA and WELIREG in helping to treat patients with certain types of renal cell carcinoma,” said Dr M Catherine Pietanza, vice president, Global Clinical Development, Merck Research Laboratories.

“These findings represent the first positive Phase 3 data for WELIREG in earlier stages of disease, as well as the first positive Phase 3 results for a HIF‑2α inhibitor and immunotherapy combination, reinforcing our commitment to exploring novel treatment approaches to improve upon established treatment paradigms for patients in need.”

The combination’s safety profile was consistent with prior studies.