Checkpoint blockade in lymphoma

Immune checkpoint blockade therapy (CBT) was born of the combination of several elements: the understanding of some of the important immune regulation pathways in humans; the recognition that tumors can engage those pathways to evade immune responses; and the clinical development of monoclonal antibodies targeting checkpoint receptors to restore effective anti-tumor immunity. This form of therapy, focused to date mostly on the cytotoxic T-lymphocyte associated protein 4 (CTLA-4) and programmed-death 1 (PD-1) pathways, has already revolutionized the treatment of several solid tumors. Hematologic malignancies (HMs) offer a promising testing ground for this strategy, and several trials have already demonstrated evidence of therapeutic activity with checkpoint blockade, especially in lymphoma. This review will discuss the current clinical results of CBT in lymphoma in the context of their scientific underpinning, and build from this summary a projection of how the field may evolve in the near future.