Allogeneic Transplant and CAR-T Therapy After Autologous Transplant Failure in DLBCL: A Noncomparative Cohort Analysis.

Allogeneic transplant (alloHCT) and chimeric antigen receptor modified (CAR) T-cell therapy are potentially cuarative options of diffuse large B-cell lymphoma (DLBCL) relapsing after an autologous (auto) HCT. While the Center for International Blood and Marrow Transplant Research (CIBMTR) prognostic model can predict outcomes of alloHCT in DLBCL after autoHCT failure, corresponding models of CAR-T treatment in similar patient populations are not available. In this noncomparative registry analysis we report outcomes of DLBCL patients (≥18 years), undergoing a reduced intensity alloHCT or CAR-T therapy during 2012-2019, after a prior auto-HCT failure, and apply CIBMTR prognostic model to CAR-T recipients. 584 patients were included. The 1-year relapse, non-relapse mortality, overall survival (OS) and progression-free survival (PFS) for CAR-T treatment after autoHCT failure were were 39.5%, 4.8%, 73.4% and 55.7%, respectively. The corresponding rates in alloHCT cohort were 26.2%, 20.0%, 65.6% and 53.8%, respectively. The 1-year OS of alloHCT recipients classified as low-, intermediate- and high/very high-risk groups according to the CIBMTR prognostic score was 73.3%, 59.9%, and 46.3, respectively (p=0.002). The corresponding rates for low-, intermediate- and high/very high-risk CAR-T patients were 88.4%, 76.4%, and 52.8%, respectively (p<0.001). This registry analysis shows that both CAR-T and alloHCT can provide durable remissions in subset of DLBCL patients relapsing after a prior autoHCT. The simple, CIBMTR prognostic score can be used to identify patients at high risk of treatment failure after either procedure. Evaluation of novel relapse mitigations strategies after cellular immunotherapies are warranted in these high risk patients.