Cladribine Combined With G-CSF and Cytarabine as a Salvage Treatment in R/R ALL

Cladribine combine with cytarabine will be intravenous on days 1-5; G-CSF will be hypodermic injection on day0-5,4 weeks per cycle.

Control arm Patients in the control arm received the investigator's choice of one of the following three regimens: FLAG:Fludarabine(30mg/m2)should be intravenous use on day 1-5, granulocyte colony-stimulating factor will be hypodermic injection using 300 μg per day on days 0-5,cytarabine (1.5 mg/m2) every 12 hours, intravenous infusion on day1-5,4 weeks per cycle. a high-dose cytosine arabinoside-based regimen; a high-dose methotrexate-based regimen