Long-term outcomes following the addition of granulocyte colony-stimulating factor-combined high-dose cytarabine to total body irradiation and cyclophosphamide conditioning in single-unit cord blood transplantation for myeloid malignancies

An intensified myeloablative conditioning regimen, involving the addition of granulocyte colony-stimulating factor (G-CSF)-combined high-dose cytarabine (12 g/m²) to standard total body irradiation and cyclophosphamide, has been performed for adult patients with myeloid malignancies in single-unit cord blood transplantation (CBT) since 1998 in our institute. We update the results of CBT, as the first allogeneic hematopoietic cell transplantation after this conditioning regimen, in 169 patients with a median long-term follow-up of 10.4 years. The median age was 43 years (range, 16 to 59 years). Ninety-four patients (56%) were in non-remission at the time of CBT, and 124 patients (73%) were acute myeloid leukemia. The median cryopreserved cord blood total nucleated cell dose and CD34⁺ cell dose was 2.40 × 10⁷/kg and 0.93 × 10⁵/kg, respectively. The cumulative incidence of neutrophil recovery at 42 days was 94.4% (95% confidence interval [CI]: 88.6–97.3%). Among the whole cohort, 105 patients were still alive at the end of the study period. The cumulative incidences of relapse and non-relapse mortality at 10 years were 26.0% (95% CI: 19.5–33.0%) and 16.9% (95% CI: 11.4–23.4%), respectively. There was an overall survival probability of 62.5% (95% CI: 54.3–69.7%) at 10 years. Higher disease risk index alone significantly affected higher overall mortality (hazard ratio 2.21, P = 0.003) in multivariate analysis. These outcomes demonstrate that G-CSF-combined myeloablative conditioning could have favorable long-term remission rates for adult patients with myeloid malignancies undergoing single-unit CBT.