Allogeneic bone marrow transplantation for chronic myelomonocytic leukemia in childhood: A report from the European Working Group on Myelodysplastic Syndrome in Childhood

Purpose: To evaluate the role of allogeneic bone marrow transplantation (BMT) in children with chronic myelomonocytic leukemia (CMML). Patients and Methods: Forty-three children with CMML given BMT and reported to the European Working Group on Myelodysplastic Syndrome in Childhood (EWOG-MDS) data base were evaluated. In 25 cases, the donor was a human leukocyte antigen (HLA)-identical or a one-antigen-disparate relative, in four cases a mismatched family donor, and in 14 a matched unrelated donor (MUD). Conditioning regimens consisted of total-body irradiation (TBI) and chemotherapy in 22 patients, whereas busulfan (Bu) with other cytotoxic drugs was used in the remaining patients. Results: Six of 43 patients (14%), five of whom received transplants from alternative donors, failed to engraft. There was a significant difference in the incidences of chronic graft- versus-host disease (GVHD) between children transplanted from compatible/one- antigen- mismatched relatives and from alternative donors (23% and 87%, respectively; P < .005). Probabilities of transplant-related mortality for children given BMT from HLA-identical/one-antigen-disparate relatives or from MUD/mismatched relatives were 9% and 46%, respectively. The probability of relapse for the entire group was 58%, whereas the 5-year event-free survival (EFS) rate was 31%. The EFS rate for children given BMT from an HLA-identical sibling or one-antigen-disparate relative was 38%. In this latter group, patients who received Bu had a better EFS compared with those given TBI (62% v 11%, P < .01). Conclusion: Children with CMML and an HLA-compatible relative should be transplanted as early as possible. Improvement of donor selection, GVHD prophylaxis, and supportive care are needed to ameliorate results of BMT from alternative donors.