Analysis of 500 bone marrow transplants from unrelated donors (UR-BMT) facilitated by the Japan Marrow Donor Program: confirmation of UR-BMT as a standard therapy for patients with leukemia and aplastic anemia.

In December 1991, the Japan Marrow Donor Program (JMDP) was established with the cooperation of the Japanese Red Cross and Japan Marrow Donor Foundation under the auspices of the Ministry of Health and Welfare in Japan. By December 1998, 122365 HLA-A,B typed volunteer marrow donors and 7207 patients had been cumulatively registered in the JMDP. The results of HLA-matching between donors and patients revealed that 5684 out of 7207 (78.9%) patients could have at least one HLA-A,B,DR serologically matched donor. Among these matched pairs, 1829 unrelated bone marrow transplants (UR-BMT) were performed. The initial 500 UR-BMT transplanted from January 1993 to October 1995 were analyzed as of July 1998. Engraftment was achieved in 95% of cases. Probability of the occurrence of grade III and IV acute GVHD was 18.4%. The rate of disease-free survival (DFS) of the patients who had standard-risk leukemia and did not suffer from grade III or IV acute GVHD (n = 154) was 60-71% and the rate of survival of patients with aplastic anemia was 56%. It can be stated that UR-BMT is a modality of treatment which is as effective as related BMT if the occurrence of grade III or IV acute GVHD is predicted and prevented.