[Reduced intensity conditioning regimen for related and unrelated allogeneic peripheral blood hematopoietic stem cell transplantation in chronic myeloid leukemia.].

Objective: To evaluate the overall efficacy and transplant-related mortality (TRM) of related and unrelated allogeneic peripheral blood hematopoietic stem cell transplantation (allo-PBSCT) in chronic myeloid leukemia (CML) patients conditioned with fludarabine-busulfan (FB) reduced intensity regimen.

Methods: Forty-four patients received FB (Flud 30 mgxm(-2)xd(-1) x 5 d, BU 4 mgxkg(-1)xd(-1) x 3 d) conditioning followed by allo-PBSCT. Of them, 29 patients were transplanted with related donor and 15 unrelated donor (URD). All patients received mycophenolate mofetil (MMF), CsA and MTX for acute GVHD (aGVHD) prophylaxis. 5 mg/kg rabbit-antithymocyte globulin (ATG-Fresenius) was incorporated in 15 URD recipients.

Results: All patients were successfully engrafted. The median times to ANC above 0.5 x 10(9)/L in related (RG) and unrelated groups (URG) were 13.7 (9 - 18) d and 13.6 (12 - 17) d, and PLT above 20 x 10(9)/L were 15.3 (9 - 20) d and 14.7 (10 - 26) d, respectively. Two patients in RG. 1 in URG developed graft rejection 5 - 8 months after transplantation. One of the two patients in RG received second transplantation and engrafted. The cumulative incidence of aGVHD and cGVHD were 13.8% (4/29) and 46.4% (13/28) in RG, and were 33.3% (5/15) and 57.1% (8/14) in URG respectively. Two patients in RG relapsed after transplantation, and obtained CR again after donor stem cell infusion (DSI). Median time of follow-up was 34.7 (2 - 73) months. Thirty-four patients were alive and 10 died. The main causes of death were IP, GVHD, graft rejection and infection. The 5-year overall survival (OS) probability was 77.0%, and the disease-free-survival (DFS) was 73.9%, of which, 79.0% and 74.1% were in RG, and 73.3% and 73.3% in URG, respectively.

Conclusions: Fludarabine-busulfan based reduced intensity conditioning for allo-PBSCT with either related or unrelated donors is a safe, less toxic and curative approach to CML.