The Japanese cord blood bank network experience with cord blood transplantation from unrelated donors for haematological malignancies: an evaluation of graft-versus-host disease prophylaxis.

Cryopreserved umbilical cord blood (CB) from unrelated donors can restore haematopoiesis after myeloablative therapy in patients with haematological malignancy. We investigated the clinical outcomes of CB transplantation (CBT) with special emphasis on graft-versus-host disease (GVHD) prophylaxis. Patients with haematological malignancies (n = 216) received intensive chemotherapy or immunosuppressive therapy, followed by transplantation of cryopreserved CB cells from unrelated donors. The clinical outcomes, i.e. haematological reconstitution, the incidence of acute or chronic GVHD, relapse and event-free survival (EFS), were evaluated. The estimated probability of neutrophil recovery was 88.2%. The median follow-up for the survivors was 557 d (range 21-1492 d). The overall and EFS rates were 32.6% and 25.5%, respectively, 3.5 years after transplantation. Multivariate analysis using Cox's proportional hazards model showed that high-risk disease status at CBT and single-drug GVHD prophylaxis were associated with worse 2-year EFS rates [P = 0.0013, relative risk (RR) 1.90, 95% confidence interval (CI) 1.28-2.81 and P = 0.0007, RR 1.91, 95% CI 1.31-2.79 respectively). Age at CBT had no significant influence on EFS. Cryopreserved CB from unrelated donors can restore haematopoiesis in patients with haematological malignancy. Although the incidence is low, the prophylaxis for acute GVHD is an important factor for survival of CBT from unrelated donors. A high rate of suitable donors was found, with a probability of 1 to every 18 CB units, when compared with human leucocyte antigen matching at other haematopoietic stem cell banks.