Low-Dose ATG Combined with Facybu Conditioning Regimen Followed By Single Unrelated Cord Blood Transplantation in Hematological Malignancies

Objective: This study aims to evaluate the efficacy and safety of low-dose ATG combined with FACyBu conditioning regimen for single unrelated cord blood transplantation in hematological malignancies

Method: From Jul 2013 to Feb 2017, 30 patients of hematological malignancies (15 patients with ALL,11 patients with AML,3 patients with NHL,1 patient with CML ) who underwent unrelated cord blood transplantation were followed up. The median age was 24(3.16-46)years. Seventeen patients were in complete remission(CR) while 13 patients were in progressive stage. All the patients were pretreated with low dose ATG(Fresenius) (24patients 10.0mg/kg/d, 6 patients 5.0mg/kg/d;d-5,d-4) plus FACyBu(a myeloablative FA-BUCY protocol of 25 mg/m²/day Fludarabine and high-dose 2 g/m²/day Cytarabine for 5 consecutive days from day −13 to day −9, 1.8g/m²/day CY from day −8 to day −7, 3.2mg/kg/day BU from day −6 to day −4 and MCCNU 250mg /m² d-3). Cyclosporine and mycophenolate were applied for Graft-versus-host disease (GVHD) prophylaxis. The GVHD, RFS, nonrelapse mortality, relapse mortality, OS, DFS and graft-versus-host disease-free/relapse-free survival (GRFS) probabilities were investigated. The side effects of the regimens were also evaluated.

Result: The median CD34⁺ cell infusion quantity was 0.17 (0.07-1.26)*10⁶/Kg. the median neutrophil engraftment time was 18(10-27)days and the median platelet engraftment time was 33(15-49)days. The cumulative incidence of grades II-IV acute GVHD was 23.5%. It's interesting that no grade III-IV acute GVHD was observed. The cumulative incidence of limited chronic GVHD and extensive chronic GVHD was 5.0% , 9.1% respectively. The median follow-up time was 10.8(2.6-46.1) months. The nonrelapse mortality, relapse mortality, OS, DFS and GRFS were 27.6%,10.9%,64.5%,64.4% and 61.4%, respectively. For the CR patients, the OS, DFS and GRFS were 85.9%, 85.9%, 80.2%, respectively. While for the nonremission patients, the OS, DFS and GRFS were 38.5%,28.5%, 38.5%

Conclusion: The clinical efficacy of low-dose ATG combined with FACyBu conditioning regimen followed by single unrelated cord blood transplantation in hematological malignancies patients is similar to that of alternative allogeneic bone marrow transplantation as reported. The incidence of GVHD was low .The patients who were treated with this regimen experience good quality of life.