Checkpoint Inhibition: Programmed Cell Death 1 and Programmed Cell Death 1 Ligand Inhibitors in Hodgkin LymphomaVillasboas, Jose Caetano MD; Ansell, Stephen MD, PhDThe Cancer Journal: January/February 2016 - Volume 22 - Issue 1 - p 17–22 doi: 10.1097/PPO.0000000000000164 Review Articles Buy Abstract Author InformationAuthors Article MetricsMetrics Hodgkin lymphoma (HL) is a lymphoid malignancy characterized by a reactive immune infiltrate surrounding relatively few malignant cells. In this scenario, active immune evasion seems to play a central role in allowing tumor progression. Immune checkpoint inhibitor pathways are normal mechanisms of T-cell regulation that suppress immune effector function following an antigenic challenge. Hodgkin lymphoma cells are able to escape immune surveillance by co-opting these mechanisms. The programmed cell death 1 (PD-1) pathway in particular is exploited in HL as the malignant Hodgkin and Reed-Sternberg cells express on their surface cognate ligands (PD-L1/L2) for the PD-1 receptor and thereby dampen the T-cell–mediated antitumoral response. Monoclonal antibodies that interact with and disrupt the PD-1:PD-L1/L2 axis have now been developed and tested in early-phase clinical trials in patients with advanced HL with encouraging results. The remarkable clinical activity of PD-1 inhibitors in HL highlights the importance of immune checkpoint pathways as therapeutic targets in HL. In this review, we discuss the rationale for targeting PD-1 and PD-L1 in the treatment of HL. We will evaluate the published clinical data on the different agents and highlight the safety profile of this class of agents. We discuss the available evidence on the use of biomarkers as predictors of response to checkpoint blockade and summarize the areas under active investigation in the use of PD-1/PD-L1 inhibitors for the treatment of HL. From the Division of Hematology, Department of Medicine, Mayo Clinic, Rochester, MN. The authors have disclosed that they have no significant relationships with, or financial interest in, any commercial companies pertaining to this article. Reprints: Jose Caetano Villasboas, MD, Division of Hematology, Department of Medicine, Mayo Clinic, 200 First St SW, Rochester, MN 55905. E-mail: email@example.com. Copyright © 2016 Wolters Kluwer Health, Inc. All rights reserved.