[Decitabine-based conditioning regimen is feasible and effective in the treatment of myelodysplastic syndrome and chronic myelomonocytic leukemia].

Objective To assess the efficacy and toxicity of decitabine-based conditioning regimen in patients with myelodysplastic syndrome (MDS) , acute myeloid leukemia secondary to MDS (MDS-AML) or chronic myelomonocytic leukemia (CMML) . Methods From March 1, 2013 to May 25, 2015, 22 patients who underwent allogenic hematopoietic stem cell transplantation (allo-HSCT) with decitabine-based conditioning regimen were analyzed retrospectively. Results ①22 patients, 14 males and 8 females with a median age of 42.5 (24-56) years old, were diagnosed as MDS (n=14) , CMML (n=4) , MDS-AML (n=4) . ②15 patients were treated with the conditioning regimen of decitabine combined with busulfan, cyclophosphamide, fludarabine, and cytarabine, the other 7 cases were treated with decitabine, busulfan, fludarabine, and cytarabine. The dose of decitabine was 20 mg·m-2·d-1 for 5 days.Rabbit anti-human anti-thymocyte globulin (2.5 mg·kg-1·d-1 for 4 days) was involved in conditioning regimen in patients with unrelated donor or haploidentical transplantation. ③Except 1 patient died of infection in 2 months after transplantation, the other patients were engrafted successfully. The median time of granulocyte engraftment was 13 (12-18) days, and the median time of platelet engraftment was 16 (13-81) days. ④The incidence of acute graft versus host disease (aGVHD) was (41.3±10.6) %, and severe aGVHD (grade of III-IV) was (18.4±9.7) %. The incidence of chronic graft versus host disease (cGVHD) was (56.4±11.3) %, and extensive cGVHD was (36.4±12.1) %. ⑤8 patients were suffered with cytomegalovirus (CMV) viremia. Among the 18 patients with definitely infection, 6 occurred during myelosuppression and 12 cases occurred after hematopoietic reconstruction. The 2-year and 3-year non-relapse mortality was (13.9±7.4) % and (24.3±9.5) %, respectively. ⑥The 2-year and 3-year overall survival (OS) was (77.3±8.9) % and (67.9±10.0) %, respectively. The 2-year and 3-year relapse-free survival (RFS) was (72.7±9.5) % and (63.6±10.3) %, respectively. Conclusions allo-HSCT with decitabine-based conditioning regimen is feasible in the treatment of MDS, MDS-AML or CMML. Key words: Decitabine; Conditioning regimen; Myelodysplastic syndrome; Chronic