Objective: To observe the treatment effect and toxicity of nonmyeloablative allogeneic stem cell transplantation (NST) for hematologic diseases.
Methods: A total of 243 hematologic diseases patients received HLA-identical NST were enrolled in this study from 9 transplant centers of NST Cooperative Group in China. Nonmyeloablative conditioning regimen was based on fludarabine (Flud), rabbit anti-human thymocyte globulin (ATG), cyclophosphamide (CTX) (FAC), and plus cytarabine or busulfan (BU) etc. Graft-versus-host disease (GVHD) prophylaxis included cyclosporin A (CsA) and mycophenolate mofetil (MMF).
Results: Among the 243 patients, 219 (90.1%) achieved full donor chimerism (FDC), 2(0.8%) engraftment failure. 78 (32.1%) had mixture chimerism (MC) at 4 weeks after NST, out of which 56 switched to FDC, 16 remained MC and 6 (2.5%) developed graft rejection. The incidence of acute GVHD was 34.2%, including 6.6% of grade III-IV acute GVHD. Chronic GVHD developed in 78 (32.1%) patients. The follow-up durations were 3 - 99 months, 162 (66.7%) were still alive and the overall survival rates were 76.5%, 73.9%, 70.7%, and 27.8% for MDS/SAA, chronic myeloid leukemia, acute leukemia at first remission, and refractory or relapsed leukemia, respectively.
Conclusions: The nonmyeloablative allogeneic stem cell transplantation based on FAC conditioning results in sustained engraftment and mild aGVHD, providing a new feasible curative therapy for hematology diseases.