Allogeneic stem cell transplantation with prior pembrolizumab and bendamustine therapy induce complete metabolic response in relapsed/refractory classical hodgkin lymphoma with relapse after nivolumab

Relapsed/refractory classical Hodgkin lymphoma (r/r cHL) poses a therapeutic challenge, particularly after failure of checkpoint inhibitors (CPIs) and brentuximab vedotin. We report a case of a heavily pretreated young male patient with r/r cHL who achieved complete metabolic response (CMR) after allogeneic hematopoietic stem cell transplantation (allo-HCT) following pembrolizumab and bendamustine therapy, currently in CMR at 19 months post-transplantation. Despite prior resistance to nivolumab, pembrolizumab combined with bendamustine contributed to disease control in the pre-transplant period. This case highlights allo-HCT's curative potential even in partial responders and suggests that pre-transplant CPI therapy may enhance the graft-versus-lymphoma effect, improving post-transplantation outcomes in r/r cHL. Another explanation for the therapeutic success may be that the employment of a CPI has likely contributed to sensitization to chemotherapy and bendamustine potentially lowering the occurrence of GvHD due to T-cell compartment impairment, with the need for large scale prospective trials to demonstrate our findings.