The trial’s second primary endpoint of overall survival is also not expected to achieve statistical significance.
Epacadostat is an investigational, potent and selective oral inhibitor of the IDO1 enzyme. Keytruda is an anti-PD-1 therapy that works by enhancing the ability of the body’s immune system to help detect and fight tumor cells.
Keytruda is a humanized monoclonal antibody that avoids the interaction between PD-1 and its ligands, PD-L1 and PD-L2.
The phase 3 randomized, double-blind and placebo-controlled study is assessing Keytruda in combination with epacadostat or placebo in patients with unresectable or metastatic melanoma.
The trial recruited more than 700 patients, which have been into randomized 1:1 and stratified by tumor PD-L1 expression (positive versus negative/indeterminate) and BRAF mutation status (BRAF mutant who have received prior BRAF-directed treatment, BRAF mutant with no prior BRAF-directed treatment and BRAF wild-type).
According to Merck, the dual primary endpoints of the trial are progression-free survival and overall survival, and secondary endpoints include objective response rate, safety and tolerability
The companies will stop the trial based on the results and recommendation of the eDMC.
Incyte chief medical officer Dr Steven Stein said: “We remain dedicated to transforming the treatment of cancer and will continue to explore how IDO1 inhibition and other novel mechanisms can potentially improve outcomes for patients in need.”
Merck Research Laboratories chief medical officer, global clinical development head and senior vice president Dr Roy Baynes said: “We look forward to sharing the comprehensive data analysis from ECHO-301/KEYNOTE-252 with the scientific community at an upcoming medical meeting.”
Image: Merck’s Keytruda. Photo: courtesy of Merck Sharp & Dohme Corp.