CLAT in Combination with HLA-mismatched Peripheral Blood Stem-Cell Microtransplantation for the Treatment of Refractory AML

Objective To investigate the efficacy and safety of cladribine combined with cytarabine and topotecan (CLAT) regimen combined with granulocyte colony-stimulating factor(G-CSF)-mobilized donor peripheral blood stem cell(G-PBSC) in the treatment of refractory acute myeloid leukemia (AML). Methods We analyzed refractory AML patients receiving programmed infusions of G-PBSC after the CLAT regimen of chemotherapy treatment. A total of 9 patients with refractory AML (median age 34 years, range 20 to 44 years, male n=7, female n=2) were treated with CLAT regimen which consisted of cladribine 5 mg/m²/d intravenously for 5 consecutive days (day 1~5) and topotecan 1.25 mg/m²/d in oral for 5 days(day 1~5) for priming combined with cytarabine of 1.5 g/m²/d q12h intravenously for 5 days (day 1~5). G-CSF of 300 μg/day subcutaneous injection on day 6 until neutrophil granulocyte count was ≥1.0×10⁹/L. Donor stem cells were transfused into the patient at CD3+ cell 1.0×10⁸/kg. Results Nine patients underwent at least one cycle of microtransplantation. After the first cycle, four patients (44.4%) achieved a complete remission (CR) and 3 patients (33.3%) achieved partial remission (PR), the overall response rate was 77.8%. Five patients had a CR rate of 55.6% after the second cycle. The median recovery time for neutrophils and platelets was 14(7~21) days and 8(0~19) days. Conclusion CLAT regimen in combination with microtransplantation was well tolerated and showed a promising clinic efficacy in patients with refractory AML.