Late Mortality and Relapse following BuCy2 and HLA-Identical Sibling Marrow Transplantation for Chronic Myelogenous Leukemia

Allogeneic hematopoietic stem cell transplantation (HSCT) is the only known curative therapy for chronic myelogenous leukemia (CML). Failure, because of relapse or nonrelapse mortality (NRM), generally occurs within 3 years of transplantation, but large studies with long-term follow-up are limited. We present mature results in 335 patients with CML who underwent allogeneic bone marrow transplantation (BMT) from HLA-identical siblings following busulfan and cyclophosphamide (BU/Cy2). Two hundred twenty-nine were in chronic phase (CP) and 106 in accelerated or blastic phase at transplantation. Median follow-up exceeded 14 years. The estimated probability of 18-year leukemia-free survival (LFS) for CP patients was 55.6% and for those beyond CP, 10.5%. Of 182 patients who survived leukemia-free at 3 years, the estimated probability of LFS at 18 years was 61.9%. Late relapse (P = .039) and late NRM (P = .008) occurred at higher rates in patients beyond CP at transplantation. There was no plateau in LFS.