Keytruda scores well in triple-negative breast cancer trial

Merck & Co (NYSE: MRK) yesterday revealed that the Phase III KEYNOTE-522 trial investigating its anti-PD-1 therapy Keytruda (pembrolizumab) 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).

This is a welcome result for the US pharma giant, whose shares ended Monday up 1.3% at $82.49 following the announcement, given that just a couple of months ago Merck released  Phase III KEYNOTE-119 trial data evaluating the anti-PD-1 therapy as monotherapy for the second- or third-line treatment of patients with metastatic TNBC that did not meet its pre-specified primary endpoint of superior overall survival compared to chemotherapy (capecitabine, eribulin, gemcitabine or vinorelbine).

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.