Minimum-Dose, Short-Term Methotrexate With Tacrolimus for Graft-vs-Host Disease Prophylaxis Following Unrelated Cord Blood Transplantation in Adults: A Retrospective Analysis at a Single Institution

Abstract Background Methotrexate (MTX) or mycophenolate mofetil with tacrolimus (TAC) is used for graft-vs-host disease (GVHD) prophylaxis in unrelated cord blood transplantation (CBT). However, there is no consensus regimen for GVHD prophylaxis in CBT. We aimed to assess the efficacy and feasibility of minimum-dose, short-term MTX (MS-MTX) for GVHD prophylaxis in CBT. Methods We retrospectively evaluated 35 consecutive adult patients who underwent CBT and received MS-MTX (6 mg/m2 day 1; 3 mg/m2 days 3 and 6, intravenously) with TAC for GVHD prophylaxis in our hospital between 2015 and 2019. Transplantation outcomes with respect to time to hematopoietic recovery, engraftment, incidence and severity of GVHD, adverse events, relapse, nonrelapse mortality (NRM), and overall survival were evaluated. Results The median time to neutrophil, platelet, and reticulocyte recovery was 22, 38, and 32 days, respectively. Cumulative neutrophil engraftment was 91.4%. After a median 3.2-year follow-up, the 2-year overall survival was 64.3%. The 2-year cumulative incidence of relapse and NRM was 20.4% and 14.9%, respectively. The 100-day cumulative incidence of grade II-IV acute GVHD and 2-year cumulative incidence of chronic GVHD were 28.6% and 36.6%, respectively. No grade IV acute GVHD was observed. Sixteen patients experienced oral mucositis and/or pharyngeal pain (46%; grades 1-2, n = 15; grade 3 pharyngeal pain, n = 1). No patients suffered from human herpesvirus 6 encephalitis/myelitis. Conclusions MS-MTX with TAC is feasible and safe and yields lower rates of severe oropharyngeal mucositis and human herpesvirus 6 encephalitis/myelitis without increasing GVHD, graft failure, relapse, or NRM.