Bone Marrow Transplants from Unrelated Donors for Patients with Chronic Myeloid Leukemia

BACKGROUND: Chronic myeloid leukemia can be cured by marrow transplantation from an HLA-identical sibling donor. The use of transplants from unrelated donors is an option for the 70 percent of patients without an HLA-identical sibling, but the morbidity and mortality associated with such transplants have been cause for concern. We analyzed the safety and efficacy of transplants from unrelated donors for the treatment of chronic myeloid leukemia and identified variables that predict a favorable outcome. METHODS: Between May 1985 and December 1994, 196 patients with Philadelphia chromosome-positive chronic myeloid leukemia in chronic phase received marrow transplants from unrelated donors. RESULTS: The median follow-up was 5 years (range, 1.2 to 10.1). Graft failure occurred in 5 percent of patients who could be evaluated. Acute graft-versus-host disease of grade III or IV severity was observed in 35 percent of patients who received HLA-matched transplants, and the estimated cumulative incidence of relapse at five years was 10 percent. The Kaplan-Meier estimate of survival at five years was 57 percent. Survival was adversely affected by an interval from diagnosis to transplantation of one year or more, an HLA-DRB1 mismatch, a high body-weight index, and an age of more than 50 years. Survival was improved by the prophylactic use of fluconazole and ganciclovir. The Kaplan-Meier estimate of survival at five years was 74 percent (95 percent confidence interval, 62 to 86 percent) for patients who were 50 years of age or younger who received a transplant from an HLA-matched donor within one year after diagnosis. CONCLUSIONS: Transplantation of marrow from an HLA-matched, unrelated donor is safe and effective therapy for selected patients with chronic myeloid leukemia.