Umbilical cord blood transplantation for adults using tacrolimus with two-day very-short-term methotrexate for graft-versus-host disease prophylaxis

•CBT is linked to problems including PIR, ES, and GF.•TAC + vsMTX reduced the risks of PIR and GF.•TAC + vsMTX promoted neutrophil engraftment.•TAC + vsMTX is an option for prophylaxis of GVHD during CBT.

Cord blood transplantation (CBT) is an alternative approach to allogeneic stem cell transplantation. However, CBT is associated with issues including pre-engraftment immune reaction (PIR), engraftment syndrome (ES), and graft failure (GF). Tacrolimus (TAC) and short-term methotrexate (sMTX: days 1, 3, 6, and/or 11) are used for graft-versus-host disease (GVHD) prophylaxis during CBT; however, sMTX does not accelerate neutrophil engraftment. Therefore, we hypothesized that lower doses of sMTX [very-short-term MTX (vsMTX): 10 and 7 mg/m2 on days 1 and 3, respectively] with TAC reduce the risk of GF without increasing post-transplantation immune reactions during CBT. We retrospectively analyzed 40 patients who received TAC with vsMTX for GVHD prophylaxis. PIR and ES developed in 4 patients. The cumulative incidence of neutrophil engraft at day 60 was 92.5%. No cases of primary graft failure were noted. The cumulative incidence of grades II–III GVHD was 48.1% at day 100, and the cumulative 100-day incidence of nonrelapse mortality was 12.5%. This study suggests that TAC with vsMTX reduces the risk of PIR and ES during CBT and stimulates neutrophil engraftment, but may be associated with slightly higher aGVHD compared with calcineurin inhibitor and sMTX. Therefore, we recommend vsMTX plus TAC as an option for GVHD prophylaxis during CBT.