Effectiveness of CLAT Protocol for Treating Patients with Refractory Acute Myeloid Leukemia

To explore the clinical efficacy and toxicity of CLAT protocol (cladribine, cytarabine and topotecan) for treating patients with refractory acute myeloid leukemia (R-AML).A total of 18 patients with R-AML (median age 37 years, range 18 to 58 years; male n = 16, female n = 2) were treated with CLAT protocol, which consisted of cladribine 5 mg/m(2)/d, i.v. on days 1-5, cytarabine 1.5 g/m(2)/d, i.v. on days 1-5, topotecan 1.25 mg/m(2)/d, i.v. on days 1-5 and G-CSF 300 µg/d subcutaneous injection on day 6 until neutrophile granulocyte recovery.Out of 18 patients 2 died of severe infection before the assessment. Among 16 evaluated patients, 10 (55.6%) achieved complete remission (CR), and 2 (11.1%) achieved partial remission (PR), the overall response rate was 66.7%, the rest 4 patients did not respond (NR). The median overall survival time and DFS for the CR patients was 9.5 months (95%CI: 6.7-16.64) and 9.5 months (95%CI: 6.1-16.7) respectively. The 1 year OS and DFS rates were 45% and 46.9%, respectively. All patients developed grade 4 of granulocytopenia and thrombocytopenia, the median duration was 13 (range 2 to 21) days and 12 days (range 2 to 21), respectively, all patients developed infection, 2 patients died of severe infection. The most common non-hematological side effects included nausea, vomiting, diarrhoea, rash, aminotransferase or bilirubin elevation and were grade 1 to 2.The CLAT protocol seems to have promising for the treatment of refractory AML patients, and patients well tolerated. This CLAT protocol offers an alternative treatment for R-AML patients who received severe intensive treatment, especially with anthracycline-containing chemotherapy.