Clinical Trials

The drug met one of its primary endpoints of pathological complete response (pCR) rate in ER+/HER2- breast cancer patients, and demonstrated a statistically significant improvement in pCR rate compared to neoadjuvant placebo plus chemotherapy.

The trial will now continue to assess the other primary endpoint of event-free survival (EFS).

Gursel Aktan, vice president of global clinical development at Merck Research Laboratories, commented: “This is the first positive phase 3 study evaluating an immunotherapy-based regimen for patients with high-risk, early-stage ER+/HER2- breast cancer, and an important milestone in our efforts to advance research in early-stage breast cancer. 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.” Fatima Cardoso, director of the Breast Unit of the Champalimaud Clinical Centre, Portugal and co-principal investigator on the trial, added: “While significant advancements have been made in the treatment of ER+/HER2- breast cancer, people diagnosed with high-risk disease as assessed by clinical and pathologic criteria typically have a worse prognosis and limited options before surgery. Data from KEYNOTE-756 suggest that adding pembrolizumab [Keytruda] to neoadjuvant chemotherapy before surgery can significantly improve the pCR rate compared to neoadjuvant chemotherapy alone for people with high-risk, early-stage ER+/HER2- breast cancer.”