Merck’s KEYTRUDA® (pembrolizumab) In Combination With Chemotherapy Met Primary Endpoint Of Pathological Complete Response (pCR) In Pivotal Phase 3 KEYNOTE-522 Trial In Patients With Triple-Negative Breast Cancer (TNBC)

Merck (NYSE: MRK), known as MSD outside the United States and Canada, today announced that the Phase 3 KEYNOTE-522 trial investigating KEYTRUDA, Merck’s anti-PD-1 therapy, in combination with chemotherapy met one of the dual-primary endpoints of pathological complete response (pCR) following the neoadjuvant part of the neoadjuvant/adjuvant study regimen in patients with triple-negative breast cancer (TNBC). Based on an interim analysis conducted by the independent Data Monitoring Committee (DMC), KEYTRUDA in combination with chemotherapy demonstrated a statistically significant improvement in pCR rates compared with chemotherapy alone, regardless of PD-L1 status. A pathological complete response or 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 previously reported studies; no new safety signals were identified.

“These findings from this innovatively designed trial with KEYTRUDA mark the first time an anti-PD-1 therapy plus chemotherapy has demonstrated a statistically significant improvement in pathological complete response rate as a neoadjuvant, or pre-surgical, segment of treatment for triple-negative breast cancer,” said Dr. Roger M. Perlmutter, president, Merck Research Laboratories. “TNBC is an aggressive malignancy with a high rate of recurrence within the first five years of diagnosis. We are encouraged by these results and plan to discuss these data with health authorities and to present these findings at an upcoming medical congress.”

The KEYTRUDA breast cancer clinical development program encompasses several internal and external collaborative studies, including three ongoing registration-enabling studies for TNBC (KEYNOTE-355, KEYNOTE-242, and KEYNOTE-522). – Bio Space