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. * Have histologically confirmed relapsed (disease progression after most recent therapy) or refractory (failure to achieve complete response \[CR\] or partial response \[PR\] to most recent therapy) classical Hodgkin Lymphoma). * Must have received at least standard first line chemotherapy for classical Hodgkin Lymphoma, containing an anthracycline. * Must have failed or declined autologous stem cell transplantation (ASCT), or not be a candidate for ASCT. * 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. * Must have Eastern Cooperative Group (ECOG) performance status 0-1. * Must have an estimated life expectancy of greater than 90 days. * Demonstrate adequate organ and bone marrow function. * If female of child-bearing potential, must have a negative pregnancy test within 72 hours prior to the first dose of study treatment. * All participants must be willing to use adequate contraception for the duration of treatment with stud…