Allogeneic transplantation after immunotherapy for relapsed/refractory non-Hodgkin lymphoma: a comparison with a historical cohort

New immunotherapy drugs, such as bispecific T-cell engager antibodies, checkpoint inhibitors and antibody–drug conjugates, are commonly used as salvage therapy for patients with non-Hodgkin lymphoma relapsing after chimeric antigen receptor T-cell (CAR-T) therapy. Nevertheless, their potential long-term effects on the outcome of allogeneic stem cell transplantation (Allo-SCT) are not well known. We retrospectively analyzed the outcomes of 27 relapsed/refractory non-Hodgkin lymphoma patients receiving an Allo-SCT after immunotherapy in the pre-CAR-T era. We compared them with a historical cohort of 28 subjects undergoing Allo-SCT after conventional therapy. The two cohorts had similar outcomes in terms of graft-versus-host disease/relapse-free survival (4 years: 59% vs 46%), overall survival (4 years: 77% vs 44%), non-relapse mortality (4 years:19% vs 22%), acute (6 months: 15% vs 21%) and chronic (4 years: 18% vs 24%) graft-versus-host disease. Of note, the cumulative incidence of relapse was lower, although significance was not reached, after immunotherapy (4 years: 4% vs 14%). The cumulative incidence of cytomegalovirus and fungal infection did not differ among the two cohorts. In conclusion, consolidation with Allo-SCT is a safe and curative option for patients achieving disease response after new immunotherapy drugs that could represent a desirable salvage strategy for patients relapsing after CAR-T.