Merck: Phase 3 Trial Met Primary Endpoint of Pathological Complete Response Rate in Early-Stage ER+/HER2- Breast Cancer

KEYTRUDA® (pembrolizumab) plus chemotherapy before surgery significantly improved pCR rate compared to neoadjuvant placebo plus chemotherapy

KEYNOTE-756 is the first positive Phase 3 study with an immunotherapy regimen to demonstrate a statistically significant improvement in pCR rate in the neoadjuvant setting for this patient population

Merck (NYSE: MRK), known as MSD outside of the United States and Canada, today 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 (pCR) 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 (ER+/HER2-) breast cancer. At a prespecified interim analysis conducted by an independent Data Monitoring Committee (DMC), 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 (EFS), 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.

"This is the first positive Phase 3 study evaluating an immunotherapy-based regimen for patients with high-risk, early-stage ER-positive, HER2-negative breast cancer, and an important milestone in our efforts to advance research in early-stage breast cancer," said Dr. Gursel Aktan, vice president, global clinical development, Merck Research Laboratories. "We look forward to sharing the detailed results with the medical community and thank the patients and investigators for their important contributions to this study."

https://finance.yahoo.com/news/merck-announces-phase-3-keynote-104500430.html