Pembrolizumab For Relapsed/Refractory Classical Hodgkin Lymphoma (R/R Chl): Phase 2 Keynote-087 Study.

7555Background: Patients (pts) with cHL who relapse after autologous stem-cell transplant (ASCT) or progress after brentuximab vedotin (BV) have a poor prognosis. The PD-1 ligands PD-L1 and PD-L2 are frequently overexpressed in R/R cHL. Pembrolizumab is a humanized monoclonal antibody against PD-1 preventing binding to PD-L1 and PD-L2. In the phase 1b KEYNOTE-013 study, pembrolizumab demonstrated high antitumor activity (ORR = 65%) in heavily pretreated cHL pts. KEYNOTE-087 (NCT02453594) is a multicohort phase 2 study designed to confirm clinical activity of pembrolizumab in cHL pts. Methods: The study has 3 cohorts: R/R cHL after ASCT and subsequent BV therapy (cohort 1); ineligible for ASCT due to chemo-resistance (no response to salvage chemotherapy) and BV therapy failure (cohort 2); R/R cHL after ASCT but not treated with BV after ASCT (cohort 3). Pts receive pembrolizumab at a fixed dose of 200 mg IV Q3W. Primary end point is ORR, with response assessed every 12 wk according to Revised Response Crit...