Merck reports Phase 3 KEYNOTE-756 trial met one of dual primary endpoints

Merck announced that the pivotal Phase 3 KEYNOTE-756 trial investigating KEYTRUDA, Merck’s anti-PD-1 therapy, in combination with chemotherapy met one of its dual primary endpoints of pathological complete response rate following the neoadjuvant part of the neoadjuvant/adjuvant study regimen in patients with high-risk, early-stage estrogen receptor-positive, human epidermal growth factor receptor 2-negative breast cancer. At a prespecified interim analysis conducted by an independent Data Monitoring Committee, the KEYTRUDA-based regimen demonstrated a statistically significant improvement in pCR rate compared to neoadjuvant placebo plus chemotherapy. A pCR is defined as a lack of all signs of cancer in tissue samples analyzed following completion of neoadjuvant therapy and definitive surgery. Based on the recommendation of the DMC, the trial will continue without changes to evaluate the other dual primary endpoint of event-free survival per the trial design. The safety profile of KEYTRUDA in this trial was consistent with that observed in previously reported studies; no new safety signals were identified. Results will be presented at an upcoming medical meeting.