[CLAG Regimen Composed of Continuous Intravenous Infusion of Cladribine in the Treatment of Refractory/Relapsed Acute Myeloid Leukemia].

Objective: To study the efficacy and safety of continuous intravenous infusion of 2-Chlorodeoxyadenosine (2-CdA) combined with high-dose cytarabine (Ara-C) and granulocyte colony-stimulating factor (G-CSF) (CLAG regiem) in the treatment of relapsed/refractory acute myeloid leukemia (AML).

Methods: Fifteen patients with refractory/relapsed AML hospitalized in 5 medical units such as Department of Hematology, the Affiliated Tumor Hospital of Zhengzhou University and received one course of CLAG regimen from June 2014 to August 2019 were analyzed retrospectively (specifically: cladribine 5 mg/M, day 1 to day 5, continuous 24-hour intravenous infusion; Ara-C 2 g/M, 1 time/day, day 1 to day 5, intravenous infusion; G-CSF 300 mg, 1 time/day, day 0 to day 5, subcutaneous injection).

Results: Among the 15 patients with refractory/relapsed AML, 9 males and 6 females, the median age was 35 (13-63) years old. FAB classification: 1 case of M, 3 cases of M, 4 cases of M (including 1 case with extramedullary invasion), 1 case of M4 with extramedullary invasion, 5 cases of M5, 1 case of HAL; NCCN classification: 6 cases in intermediate risk group, 9 cases in high risk group; 8 cases refractory, 7 cases relapsed. The median time of pre-chemotherapy was 4 (2-8) (of which NO.15 had received 8 cycles of chemotherapy and received CLL1-CAR-T), and the median white blood cell count before chemotherapy was 12.27 (from 0.78 to 5.29)×109/L. After 1 course of treatment with CLAG regimen, 12 patients achieved complete remission (12/15, 80%), and the median duration of CR was 65 days (0-528) days. IV grade leukopenia and thrombocytopenia was found in all the patients after chemotherapy. The median duration of granulocytosis was 20 (14 to 33) days, and 1 patient died. Seven patients received allogeneic hematopoietic stem cell transplantation. The median EFS and OS time of 15 patients was 85 (19-558) days and 117 (19-558) days, respectively.

Conclusion: The CLAG regimen consisting of continuous intravenous infusion of cladribine shows high CR in the treatment of AML patients, but the duration of CR is short, myelosuppression is sever, so that infection control is the key. Allogeneic hematopoietic stem cells transplantation should be performed as soon as possible after CR.