Merck, known as MSD outside the United States and Canada, and The European Organisation for Research and Treatment of Cancer (EORTC), announced that the phase 3 EORTC1325/KEYNOTE-054 trial investigating Keytruda (pembrolizumab), Merck’s anti-PD-1 therapy, as monotherapy for surgically resected high-risk melanoma, met the primary endpoint of recurrence-free survival (RFS).

Based on an interim analysis and following review by the Independent Data Monitoring Committee, post-resection adjuvant therapy with Keytruda resulted in significantly longer recurrence-free survival than placebo (HR=0.57; 98.4% CI, 0.43-0.74; p<0.0001). The safety profile of Keytruda in this trial was consistent with that observed in previously reported studies involving patients with advanced melanoma.

In accordance with the trial protocol, the study will continue in order to evaluate other key endpoints, including overall survival. Results from EORTC1325/KEYNOTE-054 will be presented at an upcoming medical meeting, and submitted to regulatory authorities.

“This has been a great collaboration between Merck and the EORTC and the findings from this interim analysis show the potential for Keytruda to significantly prolong the time before the disease recurs in patients with high-risk melanoma” said Roger Dansey, M.D., senior vice president and therapeutic area head, oncology late-stage development, Merck Research Laboratories. “This result demonstrates the meaningful benefit that Keytruda offers for patients with melanoma. We thank the patients, investigators and our partners at the EORTC for their important contributions to this study.”

“This result shows a significant advancement for patients that could potentially change the way melanoma is treated in the future,” said Alexander Eggermont, study chair, Director General at the Gustave Roussy Cancer Institute, Professor of Oncology, University of Paris-Saclay.

KEYNOTE-054 is a randomized, double-blind, phase 3 study (ClinicalTrials.gov, NCT02362594) sponsored by Merck and conducted in collaboration with the European Organisation for Research and Treatment of Cancer (EORTC). The study is evaluating adjuvant therapy with Keytruda (pembrolizumab) compared to placebo in patients with resected high-risk melanoma (Stage IIIA [> 1 mm metastasis], IIIB and IIIC). In total, the study enrolled 1,019 patients who were randomly assigned to receive either Keytruda at a flat dose of 200 mg intravenously (IV) on day 1 of each 21-day cycle for up to 1 year or placebo IV on day 1 of each 21-day cycle for up to 1 year. This represents a total of 18 outpatient administrations. The primary endpoint is RFS for all patients and RFS in patients whose tumors express PD-L1; secondary endpoints include distant metastases-free survival and overall survival in all patients and in patients whose tumors express PD-L1.