The vast majority of patients with ALL will die of the disease, and no standard chemotherapy regimen were defined for patients with relapsed/refractory ALL.Our previous experience has shown that Cladribine in combination of GAP (G-CSF priming, low dose cytarabine, and Pegaspargase) are effective with tolerable toxicity profiling.Thus, this phase 2 clincial trial is going to evaluate the efficacy and safety of cladribine in combination with G-CSF, low-dose cytarabine and Pegaspargase (C-GAP) in patients with refractory/relapsed acute Lymphoblastic Leukemia

ALL is common in the elderly patients, who can not tolerate the intensified treatments. The vast majority of patients with ALL will die of the disease, and no standard chemotherapy regimen were defined for patients with relapsed/refractory ALL. Our previous experience has shown that Cladribine in combination of GAP(G-CSF priming, low dose cytarabine, and Pegaspargase) are effective with tolerable toxicity profiling.Thus, this phase 2 clincial trial is going to evaluate the efficacy and safety of cladribine in combination with G-CSF, low-dose cytarabine and aclarubicin (C-CAG) in patients with refractory/relapsed acute myeloid leukemia.

Inclusion Criteria:

• Men and women;
• Clinical diagnosis of Relapsed/Refractory ALL;
• ECOG performance status (PS) score 0-3;
• AST and ALT <=2.5 times the institutional ULN;
• Total bilirubin <=2.0 times the institutional ULN
• Serum creatinine<2.0 times the institutional ULN;
• Subjects should take effective contraceptive measures，and serum or urine pregnancy tests must be negative during the screening and study periods in women subjects;
• Patients should understand the disease and voluntarily receive the study regimen and follow-up.

Exclusion Criteria:

• Concurrent diagnosis of tumors other than ALL, with exclusion of superficial bladder cancer, basal cell and squamous cell carcinoma, cervical intraepithelial neoplasms (CIN), prostatic intraepithelial neoplasms(PIN);
• Active viral or bacterial infection that would impair the ability of the subject to receive protocol therapy;
• Concurrent autoimmune hemolytic anemia or immune thrombocytopenia;
• Subjects suffered from AIDS，active hepatitis B or C virus infection;
• Dementia or altered mental status that would prohibit the understanding or rendering of informed consent;
• Be allergic to any component of C-GAP regimen;
• Subjects ever exposed to cladribine or CAG-based regimen.