Merck announces results from KEYNOTE-756 trial at ESMO Congress

Merck announced the first presentation of results from the neoadjuvant part of the Phase 3 KEYNOTE-756 trial investigating Keytruda, Merck’s anti-PD-1 therapy, in combination with chemotherapy as neoadjuvant treatment, followed by Keytruda plus endocrine therapy as adjuvant treatment, for patients with high-risk, early-stage estrogen receptor-positive, human epidermal growth factor receptor 2-negative breast cancer. Keytruda plus chemotherapy before surgery met one of its dual primary endpoints of pathological complete response, or pCR, demonstrating a statistically significant improvement in pCR rate compared to placebo plus chemotherapy. The pCR rate increased from 15.6% in patients treated with neoadjuvant chemotherapy alone to 24.3% in patients treated with neoadjuvant Keytruda plus chemotherapy, an estimated increase of 8.5 percentage points. A pCR rate is defined as a lack of all signs of cancer in tissue samples analyzed following completion of neoadjuvant therapy and definitive surgery. The trial is currently continuing without changes to evaluate event-free survival, or EFS, the other dual primary endpoint of the study, per the trial design. These pCR results are being featured during a late-breaking proffered paper session at the European Society for Medical Oncology, or ESMO, Congress 2023. The safety profile of Keytruda in this trial was consistent with that observed in previously reported studies.