Checkpoint Inhibitors and the Changing Face of the Relapsed/Refractory Classical Hodgkin Lymphoma Pathway

PURPOSE OF REVIEW: Checkpoint inhibitors (CPIs) targeting PD1 are highly active in relapsed/refractory classical Hodgkin lymphoma. A plethora of recent studies, often small and non-randomised, have raised many questions about how to optimally integrate these into clinical practice. We aim to discuss the use of CPIs in different relapsed/refractory settings in an effort to better define their role and highlight areas of research. RECENT FINDINGS: CPIs have shown efficacy at first relapse, as salvage pre- and post-autologous (ASCT) and allogeneic stem cell transplant (alloSCT) and as maintenance post-ASCT. Immune-related adverse events require careful attention, especially when used peri-alloSCT, where it is associated with hyperacute graft-versus-host disease. Newer PD1 inhibitors, as well as strategies to overcome CPI resistance, are being tested. SUMMARY: CPIs are increasingly deployed at earlier points in the classical Hodgkin lymphoma pathway. Whilst progress is clearly being made, randomised studies are required to more clearly define the optimal positioning of these agents.