CD274 and ovarian cancer: In the open-label, phase 2 KEYNOTE-100 trial in patients with advanced recurrent ovarian cancer, the anti-PD-L1 monoclonal antibody pembrolizumab showed a modest ORR of 7.4% in cohort A (1–3 prior regimens; platinum-free interval [PFI] or treatment-free interval [TFI] 3–12 months) and 9.9% in cohort B (4–6 prior regimens; PFI or TFI ≥3 months) (22).