Reduced-Toxicity Myeloablative Conditioning Consisting of Fludarabine/Busulfan/Low-Dose Total Body Irradiation/Granulocyte Colony-Stimulating Factor-Combined Cytarabine in Single Cord Blood Transplantation for Elderly Patients with Nonremission Myeloid Malignancies.

The optimal intensity of a conditioning regimen might be dependent on not only age and comorbidities but also disease activity and the type of graft source. We evaluated the outcome of unrelated single cord blood transplantation (CBT) using a conditioning regimen of fludarabine 180 mg/m2, i.v. busulfan 9.6 mg/kg, 4 Gy total body irradiation, granulocyte colony-stimulating factor-combined high-dose cytarabine (12 g/m2) in 23 elderly patients (median, 64 years) with nonremission myeloid malignancies between 2013 and 2018 in our institution. All but 1 patient achieved neutrophil engraftment at a median of 23.5 days (range, 18 to 50). With a median follow-up of 28 months, the probabilities of overall survival (OS), disease-free survival (DFS), and cumulative incidence of relapse at 2 years were 62%, 52%, and 26%, respectively. The cumulative incidences of nonrelapse mortality at 100 days and 2 years were 9% and 22%, respectively. In the univariable analysis a higher proportion of blasts in bone marrow and in peripheral blood and a monosomal or complex karyotype were significantly associated with inferior OS and DFS. Poor cytogenetics were significantly associated with inferior DFS and increased relapse incidence. These data demonstrate that this reduced-toxicity myeloablative conditioning regimen was tolerable and effective in terms of engraftment, relapse, and survival in single CBT for elderly patients with nonremission myeloid malignancies.