Program death inhibitors in classical Hodgkin's lymphoma: a comprehensive review.

Cancer cells are able to induce immune system tolerance through different mechanisms. Recent achievements in the understanding of tumor microenvironment, invasion, and metastasizing have contributed to accelerated drug developments and approvals. Hodgkin lymphoma (HL) cells are the minority in a lymphocyte-rich microenvironment of HL tissue. The program death-1 (PD-1)/PD-ligand-1 checkpoint is one of the known effective pathways in classical HL to escape the immune system cells. The approval of PD-1 inhibitors in different cancer types with exciting response rates is truly revolutionizing our treatment armamentarium against cancer in general and classical HL in specific. Although the disease is one of the most curable tumors, we still need better outcome with more gentle treatment, especially for relapsed and refractory (r/r) patients. In this article, we review the current literature on immune checkpoint inhibitors and currently ongoing studies with nivolumab and pembrolizumab in r/r classical HL.