Decitabine Combined with FB3 As Conditional Regimen for Elderly/Weak Acute Myeloid Leukemia Patient with Allo-HSCT

Objective Acute myeloid leukemia (AML) is one of the most common malignant hematological diseases, with a median age of 65 years. Allogeneic hematopoietic stem cell transplantation (allo-HSCT) is an important means for the treatment of AML. Elderly and weak AML patients are difficult to bear the myeloablative conditioning, and transplantation-related mortality (TRM) is significantly higher than that of young AML patients. How to reduce TRM in elderly / weak AML patients, improve the efficacy of allo-HSCT, and further expand the applicable population of allo-HSCT is a clinical problem worthy of discussion.

Methods Our center designed decitabine combined with FB3 as conditional regimen (decitabine 20mg / m² × 5 days, fludarabine 30mg / m² × 5 days, busulfan 130mg / m² × 3 days) for elderly / weak AML patients with allo-HSCT. The recurrence rate, disease-free survival rate, overall survival rate and incidence of transplantation-related complications were observed.

Results Up to July 2022, a total of 40 AML patients were enrolled, with a median age of 55 (23-65) years. 16 middle-risk group and 24 high-risk group in cytogenetics; HLA identical allogeneic hematopoietic stem cell transplantation was performed in 18 patients and HLA haploidentical hematopoietic stem cell transplantation in 22 patients. Hematopoietic reconstruction was not performed in 2 patients. Hematopoietic reconstruction was performed in 38 patients (98 % -100 %). The median time of neutrophil reconstruction was 16 (11-69) days, and the median time of platelet reconstruction was 19 (12-80) days. Among them, 7 patients died (1 patient died of severe acute graft-versus-host disease combined with pulmonary infection, 2 patients died of hematopoietic reconstitution infection, and 4 patients died of recurrence), and 8 patients complicated with invasive pulmonary fungal disease. The overall tolerance of patients with decitabine combined with FB3 was good. The main adverse reactions during condition included dizziness, nausea, vomiting, diarrhea and oral ulcer. Symptoms were relieved after symptomatic treatment. Transient transaminase increased slightly in 4 patients, and improved after liver protection treatment. The median follow-up was 36 (1-73) months. The 2-year leukemia-free survival (LFS) estimated rate was 77.5 %, and the 2-year overall survival (OS) estimated rate was 82.5 %.

Conclusion Patients can tolerate decitabine combined with FB3 regimen, achieve complete donor hematopoietic reconstruction, and has high OS and LFS. It is an alternative conditional regimen for elderly and weak AML patients with allogeneic hematopoietic stem cell transplantation. The follow-up prospective control clinical study further verifies its effectiveness and safety.

No relevant conflicts of interest to declare.