Pembrolizumab plus Chemotherapy Improves Survival in Triple-Negative Breast Cancer

Pembrolizumab, an immune checkpoint inhibitor widely used in many malignancies, was recently shown to benefit select patients with metastatic breast cancer. Researchers now report final results of the industry-sponsored phase 3 KEYNOTE-355 trial, which compared pembrolizumab plus chemotherapy in patients with metastatic, program death ligand 1 (PD-L1)–positive, triple-negative breast cancer (TNBC).

A total of 847 previously untreated patients with metastatic TNBC were randomly assigned (2:1) to pembrolizumab (200 mg every 3 weeks) plus chemotherapy or placebo plus chemotherapy. Chemotherapy options included nab-paclitaxel, paclitaxel, or gemcitabine plus carboplatin. PD-L1 status was assessed using the combined positive score (CPS) determine…