Key clinical point: First-line treatment with pembrolizumab and chemotherapy improved overall survival (OS) compared with chemotherapy alone in patients with advanced triple-negative breast cancer (TNBC) whose tumors expressed programmed death ligand 1 (PD-L1) with a combined positive score (CPS) of ≥10.
Major finding: Pembrolizumab+chemotherapy vs placebo+chemotherapy improved OS in patients whose tumors expressed PD-L1 with a CPS of ≥10 (hazard ratio for death 0.73; P = .0185); however, no survival benefits were observed in patients with PD-L1 CPS of ≥1 ( P = .1125). Grade ≥3 adverse events were reported by 68.1% and 66.9% of patients in the pembrolizumab+chemotherapy and placebo+chemotherapy groups, respectively.
Study details : Findings are from an interim analysis of the phase 3 KEYNOTE-355 trial including 847 patients with locally recurrent inoperable or metastatic TNBC who were randomly assigned to receive pembrolizumab+chemotherapy or placebo+chemotherapy.
Disclosures: This study was funded by Merck Sharp and Dohme. Four authors declared being employees of or owning stocks in Merck, and the other authors reported ties with several sources, including Merck.
Source: Cortes J et al. Pembrolizumab plus chemotherapy in advanced triple-negative breast cancer. N Engl J Med. 2022;387:217-226 (Jul 21). Doi: 10.1056/NEJMoa2202809