Merck & Co – known as MSD outside the US and Canada – has shared positive topline results from a late-stage study of its oral HIF-2α inhibitor in patients with advanced renal cell carcinoma (RCC).
The phase 3 LITESPARK-005 trial has been evaluating Welireg (belzutifan), which the company picked up in 2019 through its $1.1bn buyout of Peloton Therapeutics, for use in adults with RCC that has progressed following PD-1/L1 checkpoint inhibitor and vascular endothelial growth factor-tyrosine kinase inhibitor (VEGF-TKI) therapies.
According to data from a pre-specified interim analysis of the study, Welireg showed a statistically significant and clinically meaningful improvement in progression-free survival compared to Novartis’ Afinitor (everolimus).
A statistically significant improvement in the trial’s key secondary endpoint of objective response rate was also shown, said Merck, adding that a trend towards improvement in overall survival was observed but was not statistically significant. The company will look at overall survival in a future analysis.
RCC is the most common type of kidney cancer, accounting for about 90% of all kidney cancer diagnoses.
Most cases of RCC are discovered incidentally during imaging tests for other abdominal diseases and, in the US, approximately 15% of patients with kidney cancer are diagnosed at an advanced stage.
LITESPARK-005 is the first phase 3 trial to show positive results in advanced RCC following prior treatment with a checkpoint inhibitor and a VEGF-TKI therapy and the first new mechanism to demonstrate potential in the disease in recent years, according to Merck Research Laboratories senior vice president and late-stage oncology head, Marjorie Green.
“Patients with advanced RCC face low survival rates, and for those whose cancer progresses following PD-1/L1 and VEGF-TKI therapies, there is a need for new treatment options that can reduce their risk of disease progression or death,” Green said.
Welireg is already approved in the US to treat adults with von Hippel-Lindau disease who require therapy for associated RCC, central nervous system haemangioblastomas, or pancreatic neuroendocrine tumours not requiring immediate surgery.
LITESPARK-005 is part of a wider development programme for Welireg comprising four phase 3 trials in RCC, including two evaluating the therapy in the second-line and treatment-naïve advanced disease settings, and one in the adjuvant setting.