Varga A, et al. - In patients with programmed death ligand 1 (PD-L1)–expressing advanced ovarian cancer, researchers assessed safety, tolerability, and antitumor activity of pembrolizumab (10 mg/kg every 2 weeks) monotherapy. In this multicohort, phase Ib KEYNOTE-028 trial, key inclusion criteria were age ≥18 years; advanced ovarian epithelial, fallopian tube, or primary peritoneal carcinoma; failure of previous therapy; and tumor PD-L1 positivity. In patients with advanced PD-L1–positive ovarian cancer, pembrolizumab offered durable antitumor activity with manageable safety and toxicity. Arthralgia, nausea, and pruritus were treatment-related adverse events.