GVHD prophylaxis by tacrolimus and mini-MTX in single-unit CBT: a single institute experience.

Tacrolimus (TAC) combined with short-term methotrexate (MTX) is widely used to prevent graft-versus-host disease (GVHD) in cord blood transplantation (CBT). As short-term MTX aggravates mucositis and delays engraftment, we reduced the dose of MTX, as previously reported in the non-CBT setting. Here, we retrospectively analyze outcomes of 20 patients who received CBT from April 2017 to December 2018. All patients received TAC with mini-MTX as GVHD prophylaxis. Mini-MTX was administered at a dose of 5 mg/m2 of MTX on days 1, 3 and 6 after CBT. Median age was 54.5 years. Median follow-up time in surviving patients was 396 days. The primary disease was acute leukemia (n = 12) or malignant lymphoma (n = 8). Three patients and 17 patients received myeloablative and reduced-intensity conditioning, respectively. Rate and median time to engraftment of neutrophils were 90.0% and 20.5 days, respectively. Cumulative incidences of grade II-IV and grade III-IV acute GVHD were 35.0% and 5.0%, respectively. At one year after CBT, the overall survival rate was 80.5%, cumulative incidence of relapse/progression was 15.0%, and non-relapse mortality rate was 5.0%. In conclusion, TAC with mini-MTX may be a promising GVHD prophylaxis regimen in single-unit CBT.