Objectives:To explore the synergistic effect of CLAG combination with HHT in cell experiments and to evaluate the effectiveness and safety of the CLHAG regimen for patients with relapsed/refractory acute myeloid leukemia(R/R-AML).

Methods:In thecell experiments, the Kasumi-1 cell line was treated with a single drug or CLAG combined with HHT. MTT colorimetric method was used to determine the cell growth inhibition rate(GIR). CompuSyn drug cooperation software was used to assess the synergistic effect.In the clinical study,eligible R/ R-AML patients (n=24) were included and CLHAG regimen (cladribine 5mg/m2, d1-5, arabinoside cytosine 2g/m2 q12h, d1-5, homoharringtonine 2mg/m2, d1-d5, GCSF 300μg, d0-d5, WBC>20×109/L disuse) was performed.The efficacy was evaluated by CR, PR, ORR, PFS, OS, and ED. The safety were evaluated by hematological toxicity and non-hematological toxicity.

Results:The GIR value with a combined treatmentregimenwas higher than the sum that with the single drug treatment, showing thata synergistic effect. Twenty-four patients with R/R-AML were included in the clinical study, including 2 cases of sAML (MDS transformation), 8 cases of primary refractory, and 14 cases of relapse.The total ORR was 70.8%; among them,14 cases achieved complete remission, and 3 cases achieved partial remission. Besides, seven patients underwentallo-HSCTsuccessfully. In this study, all patients were well tolerated, and early death was not observed. The IV grade hematological toxicity was the major adverse reaction, and no IV grade non-hematological toxicity occurred.

Conclusions:TheCLHAG regimen is well tolerated and has a high remission rate in R/R-AML patients, and it can be used as a choice of salvage treatment for R/R-AML patients.

Disclosures

No relevant conflicts of interest to declare.

Author notes

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Asterisk with author names denotes non-ASH members.