Case-matched comparison with standard versus reduced intensity conditioning regimen in chronic myeloid leukemia patients

This retrospective case-matched study evaluated the efficacy of reduced intensity conditioning (RIC) regimen on early and late allogeneic transplant outcome in chronic myeloid leukemia (CML) patients. Twenty-eight patients conditioned with RIC regimen were matched to 56 patients who received a myeloablative conditioning (MAC) regimen. The main criteria for case matching among our CML allotransplant cohort were the Gratwohl scoring system. The median score was 2 (1-4) in each group. The pretransplant disease status was first chronic phase (CP1, n = 20), CP2 (n = 2), and advanced phase (n = 6) in RIC, and CP1 (n = 46), CP2 (n = 3), and advanced phase (n = 7) in MAC. The duration of neutropenia and thrombocytopenia was shorter in RIC than MAC. The grade and duration of mucositis were less in RIC. The need for total parenteral nutrition (21% vs. 77%, p < 0.0001) and febrile neutropenic episodes (50% vs. 95%, p < 0.0001) were observed less frequently in RIC compared with MAC-given patients. Acute or chronic graft versus host diseases (GvHD) were not affected by the intensity of conditioning regimen. The incidence of transplant-related mortality was higher in MAC (7% vs. 14%, p = 0.01). Although more relapse/progression was observed in the RIC group, the probability of 5- and 10-year leukemia-free- and overall survival were similar regardless of conditioning regimen intensity (p > 0.05). In early first CP, the pair of female donor-male recipient and the development of chronic GvHD prolonged both leukemia-free survival and overall survival in multivariate analysis. According to our single-center matched-pair analysis, the use of RIC regimens in patients with low-risk CML results with toxicities less, responses later, and relapses more frequent than the MAC regimens.