Studies targeting cladribine in combination with granulocyte colony-stimulating factor, low-dose cytarabine, and aclarubicin (C-CAG) regimen in relapsed and refractory acute myeloid leukemia (R/R AML) are limited. The complete remission rate after two cycles of C-CAG regimen was 67.6%, and 1-year overall survival and disease-free survival rates were 59.7% and 72.9%, respectively. The C-CAG regimen is significantly effective against R/R AML with a low hematological toxicity and thus serves as an alternative treatment for R/R AML. The optimal salvage chemotherapy regimen for relapsed and refractory acute myeloid leukemia (R/R AML) remains uncertain. Therefore, a phase II study was conducted for the prospective evaluation of the efficacy and safety of the purine analog cladribine in combination with granulocyte colony-stimulating factor (G-CSF), low-dose cytarabine, and aclarubicin (C-CAG) regimen for patients with R/R AML. A total of 34 patients received C-CAG regimen for salvage treatment as follows: cladribine 5 mg/m2 , days 1-5; G-CSF 300 μg, days 0-9; aclarubicin 10 mg, days 3-6; cytarabine 10 mg/m2 every 12 hours, subcutaneously, days 3-9; 4 weeks per cycle. Patients were allowed to withdraw from the study if complete remission (CR) was not achieved after two courses of chemotherapy. If conditions were right, the patients achieving CR were recommended to receive allogeneic hematopoietic stem cell transplantation. Otherwise, they were treated for a total of six cycles unless disease progression or unacceptable side effects were observed or they withdrew their consent. All patients received at least two cycles of C-CAG regimen chemotherapy. After two cycles of C-CAG, 23 patients (67.6%) achieved CR, and 5 patients had partial remission (14.7%). At a median follow-up of 15 months (range, 3-38 months), the 1-year overall survival (OS) and disease-free survival (DFS) rates were 59.7% (95% confidence interval [CI], 42.6%-76.8%) and 72.9% (95% CI, 54.3%-91.5%), respectively. The most common adverse effect was myelosuppression. Nonhematological toxicities were mild, and no treatment-related deaths occurred. Preliminary data indicate that the C-CAG regimen chemotherapy is significantly effective against R/R AML with a high remission rate and a low hematological toxicity. Thus, it may serve as an alternative treatment for R/R AML. © AlphaMed Press 2020.