Epacadostat Combined With Pembrolizumab in Patients With Unresectable or Metastatic Melanoma

On April 6, an external data monitoring committee commented on results from the phase III ECHO-301/KEYNOTE-252 trial of the investigational IDO1 inhibitor epacadostat plus pembrolizumab (Keytruda) in patients with unresectable or metastatic melanoma. The committee determined that the study did not meet its primary endpoint of improving progression-free survival with the combination compared to pembrolizumab monotherapy. 

The study’s second primary endpoint of overall survival is also not expected to reach statistical significance. Based on these results, and at the recommendation of the data monitoring committee, the study will be stopped.

The safety profile observed in ECHO-301/KEYNOTE-252 was consistent with that observed in previously reported studies of epacadostat in combination with pembrolizumab.

Study sponsors Incyte and Merck will inform investigators of the results and work with investigators to appropriately conclude the study in a manner consistent with the best interests of each patient. Data from this study will be analyzed and submitted for presentation at an upcoming scientific congress.

“While we are disappointed that this study did not confirm the efficacy of epacadostat in combination with pembrolizumab in patients with unresectable or metastatic melanoma, data from ECHO-301/KEYNOTE-252, including analyses of an extensive biomarker panel, will contribute to our understanding of the role of IDO1 inhibition in combination with programmed cell death protein 1 (PD-1) antagonists, and may inform our broader epacadostat clinical development program,” said Steven Stein, MD, Chief Medical Officer of Incyte.

About ECHO-301/KEYNOTE-252

This phase III randomized, double-blind, placebo-controlled study is evaluating pembrolizumab in combination with epacadostat or placebo in patients with unresectable or metastatic melanoma. ECHO-301/KEYNOTE-252 enrolled over 700 patients, randomized 1:1, and stratified by tumor programmed cell death ligand 1 (PD-L1) expression (positive vs 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). 

The dual primary endpoints of the study are progression-free survival and overall survival. Key secondary endpoints include objective response rate, safety, and tolerability.

The content in this post has not been reviewed by the American Society of Clinical Oncology, Inc. (ASCO®) and does not necessarily reflect the ideas and opinions of ASCO®.




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