Study of Pembrolizumab With Bendamustine in Hodgkin Lymphoma

Inclusion Criteria: * Be willing and able to provide written informed consent for the trial and adhere to trial procedures. * Be age ≥18 years at the time of signing informed consent. * Have histologically confirmed relapsed (disease progression after most recent therapy) or refractory (failure to achieve CR or PR to most recent therapy) classical Hodgkin Lymphoma (RR HL). * Must have received at least standard first line chemotherapy for classical Hodgkin Lymphoma, containing an anthracycline, i.e. ABVD or BEACOPP. * Must have failed or declined autologous stem cell transplantation (ASCT), or not be a candidate for ASCT (as per institutional criteria). * May have received prior therapy with pembrolizumab (or an equivalent checkpoint inhibitor or anti-PD-L1 antibody), but not in combination with bendamustine. * May have received a prior autologous stem cell transplant but must be at least ≥100 days post-auto-transplant, and all transplant- related adverse events must have resolved to a grade 1 or less, and patients are not on immunosuppression, and meet all other eligibility criteria. * Must have measurable or evaluable disease, as defined as at least one lesion that can be accurately measured in at least 2 dimensions by CT/PET scan. The minimum measurement must be \>15 mm in the longest dimension or \>10 mm in the short axis. Baseline FDG-PET scan must be positive (i.e. FDG-avid HL). Measurements must be done within 28 days prior to trial inclusion.. * Must have Eastern Coo…