The Role of Donor Lymphocyte Infusion (DLI) in Post-Hematopoietic Cell Transplant (HCT) Relapse for Chronic Myeloid Leukemia (CML) in the Tyrosine Kinase Inhibitor (TKI) Era

Treatment for relapse of chronic myeloid leukemia (CML) following hematopoietic cell transplantation (HCT) includes tyrosine kinase inhibitors (TKIs) with or without donor lymphocyte infusions (DLIs), but the most effective treatment strategy is unknown. This study was performed through the Center for International Blood and Marrow Transplant Research (CIBMTR) database. We retrospectively reviewed all patients reported to the CIBMTR registry from 2002 to 2014 who underwent HCT for CML and were alive 30 days postrelapse. A total of 215 HCT recipients relapsed and were analyzed in the following groups: (1) TKI alone (n = 128), (2) TKI with DLI (n = 48), and (3) DLI without TKI (n = 39). In multivariate analysis, disease status prior to HCT had a significant effect on overall survival (OS). Patients who received a DLI alone compared with a TKI with a DLI had inferior survival (hazard ratio, 2.28; 95% confidence interval, 1.23 to 4.24; P= .009). Those who received a TKI alone had similar survival compared with those who received a TKI with a DLI (P = .81). These data support that despite use of TKIs pretransplantation, TKI salvage therapy continues to provide significant survival following relapse in patients with CML following HCT. These data do not suggest that adding a DLI to a TKI adds an improvement in OS.