Abstract
tumor, death, breast cancer, toxicity, PD‐L1
CPS, TUMOR, BREAST CANCER
Pembrolizumab plus chemotherapy improved progression‐free survival (PFS) and overall survival (OS) compared with placebo plus chemotherapy in patients with previously untreated locally recurrent inoperable or metastatic triple‐negative breast cancer with tumor programmed cell death ligand 1 (PD‐L1) combined positive score (CPS) ≥10 in the global, phase 3, randomized controlled trial KEYNOTE‐355. We report results for patients enrolled in Japan. Patients were randomized 2:1 to pembrolizumab 200 mg or placebo Q3W for 35 cycles plus chemotherapy (nab‐paclitaxel, paclitaxel, or gemcitabine–carboplatin). Primary endpoints were PFS per RECIST version 1.1 by blinded independent central review and OS in patients with PD‐L1 CPS ≥10, PD‐L1 CPS ≥1, and the intention‐to‐treat (ITT) population. No alpha was assigned to this exploratory analysis. Eighty‐seven patients were randomized in Japan (pembrolizumab plus chemotherapy, Overall survival was prolonged with pembrolizumab plus chemotherapy compared with placebo plus chemotherapy among patients with previously untreated locally recurrent inoperable or metastatic triple‐negative breast cancer enrolled in the global, phase 3 randomized controlled trial KEYNOTE‐355. In this analysis of outcomes in patients in KEYNOTE‐355 who were enrolled in Japan, pembrolizumab plus chemotherapy improved overall survival versus placebo plus chemotherapy in patients with previously untreated locally recurrent inoperable or metastatic triple‐negative breast cancer with manageable toxicity.
Clinical trial registration: 