Merck presents data from pivotal neoadjuvant/adjuvant Phase 3 KEYNOTE-522 trial
Merck announced results from the pivotal neoadjuvant/adjuvant Phase 3 KEYNOTE-522 trial in patients with early-stage triple-negative breast cancer. The trial investigated a regimen of neoadjuvant KEYTRUDA, Merck's anti-PD-1 therapy, plus chemotherapy, followed by adjuvant KEYTRUDA as monotherapy compared with a regimen of neoadjuvant chemotherapy followed by adjuvant placebo. In the neoadjuvant phase, KEYTRUDA plus chemotherapy resulted in a statistically significant increase in pathological complete response versus chemotherapy, from 51.2% with neoadjuvant chemotherapy to 64.8% for neoadjuvant KEYTRUDA plus chemotherapy, in patients with early-stage TNBC. Pathological complete response, one of the dual primary endpoints was defined as ypT0/Tis ypN0. The improvement seen when adding KEYTRUDA to neoadjuvant chemotherapy was observed regardless of PD-L1 expression. In the other dual primary endpoint of event-free-survival, with a median follow-up of 15.5 months, the KEYTRUDA regimen reduced the risk of progression in the neoadjuvant phase and recurrence in the adjuvant phase by 37% - a favorable trend for EFS - compared with the chemotherapy-placebo regimen. The safety profiles of KEYTRUDA and chemotherapy in KEYNOTE-522 were consistent with previous studies. As previously announced, KEYTRUDA plus chemotherapy was granted Breakthrough Therapy designation by the U.S. Food and Drug Administration for the neoadjuvant treatment of patients with high-risk, early-stage TNBC. The BTD was granted based on data from Phase 1b KEYNOTE-173 and Phase 2 I-SPY2 trial, which demonstrated encouraging anti-tumor activity with neoadjuvant KEYTRUDA plus chemotherapy in these patients. As previously announced, Merck plans to share early interim analysis data from KEYNOTE-522 with regulatory authorities. The company continues to progress a robust clinical development program for KEYTRUDA in breast cancer, which encompasses several internal studies and external collaborative trials, including KEYNOTE-355 and KEYNOTE-242.