Anti-programmed cell death-1 monoclonal antibody therapy before or after allogeneic hematopoietic cell transplantation for classic Hodgkin lymphoma: a literature review

Approximately 10-30% of patients with classic Hodgkin lymphoma (cHL) have relapsed or refractory (r/r) disease after standard first-line therapy. Clinical trials have shown an acceptable safety profile and high response rate for anti-programmed cell death-1 monoclonal antibodies (anti-PD-1 mAbs) in patients with r/r cHL. Although anti-PD-1 mAbs have significantly increased treatment options for r/r cHL, most patients eventually relapse. In the current era, allogeneic hematopoietic cell transplantation (allo-HCT) is still a clinical option for r/r cHL. Anti-PD-1 mAbs have been explored as bridging therapy to allo-HCT and salvage therapy for relapse after allo-HCT. Although early reports showed increased risks of severe graft-versus-host disease (GVHD) in patients who received anti-PD-1 mAb before or allo-HCT, survival outcomes were favorable, suggesting the feasibility of PD-1 blockade around the time of allo-HCT. Based on clinical and biological data, posttransplant cyclophosphamide-based GVHD prophylaxis is a promising strategy to reduce GVHD and improve survival after allo-HCT following PD-1 blockade. Close monitoring and early intervention are needed for treatment-emergent GVHD following PD-1 blockade after allo-HCT. Further studies with a larger cohort and extended follow-up will provide insights into better patient selection, optimal dosing, and strategies to manage complications of PD-1 blockade in the context of allo-HCT.