Cladribine (5 mg/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.

Patients in the control arm received the investigator's choice of one of the following three regimens:

1. 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.
2. a high-dose cytosine arabinoside-based regimen;
3. a high-dose methotrexate-based regimen

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

Response to CLAG regimen.

The time from randomization to death from any cause.

It is defined as the total survival of a patient after CR until the tumor recurrence or death from any cause.