Safety and Antitumor Activity of Pembrolizumab in Advanced Programmed Death Ligand 1–Positive Endometrial Cancer: Results From the KEYNOTE-028 Study

Purpose The multicohort phase Ib KEYNOTE-028 (NCT02054806) study was designed to evaluate the safety and efficacy of pembrolizumab, an anti-programmed death 1 monoclonal antibody, in patients with programmed death ligand 1 (PD-L1) -positive advanced solid tumors. The results from the advanced endometrial cancer cohort are reported. Patients and Methods Female patients with locally advanced or metastatic PD-L1-positive endometrial cancer who had experienced progression after standard therapy were eligible. Patients received pembrolizumab 10 mg/kg every 2 weeks for up to 24 months or until progression or unacceptable toxicity. Primary efficacy end point was objective response rate by RECIST (version 1.1).…