First approval for Keytruda in the breast cancer setting

On Friday, the Food and Drug Administration granted accelerated approval for Keytruda (pembrolizumab), Merck & Co’s (NYSE: MRK) blockbuster PD-1 inhibitor cancer drug, in combination with chemotherapy for the treatment of patients with locally recurrent unresectable or metastatic triple-negative breast cancer (TNBC) whose tumors express PD-L1 (CPS ≥10) as determined by an FDA approved test.

News of the expanded indication for Keytruda, which generated sales of $2.2 billion in the third quarter of 2020 (up 24% year-on-year), sent Merck’s shares up 1.5% by close of trading.

The approval is based on results from the Phase III KEYNOTE-355 trial, where Keytruda in combination with chemotherapy – paclitaxel (pac), paclitaxel protein-bound (commonly known as nab-paclitaxel) or gemcitabine (gem) and carboplatin (carbo) – significantly reduced the risk of disease progression or death by 35% for patients whose tumors express PD-L1 (CPS ≥10) versus the same chemotherapy regimens alone (HR=0.65 [95% CI, 0.49, 0.86]; p=0.0012).