 Maximum tolerated dose MTD of cyclophosphamide will be determined in accordance with the standard 33 method, testing three dose levels, 150mgm2, 200mgm2 and 250mgm2. Cyclophosphamide dose escalation test will be conducted in the first cycle, with every three patients in a group. Patients enrollment will be competed among different sites, but further step should be taken only after the 3 patients in one group complete the first cycle, their efficacy and safety have been completely evaluated, and the notification of going to next step by a CRO company. Subjects involved in the cyclophosphamide dose escalation test will continue initial cyclophosphamide dose during the entire study, except for possible dose adjustment determined by investigators due to DLT. After ascertaining MTD, new patients will be administrated with cyclophosphamide at the MTD. According to the dose escalation diagram, up to 18 patients will be involved in dose escalation phase. Subjects who discontinue the treatment due to causes other than DLT in the first cycle should be replaced by new participants to enter dose escalation test. DLT is defined as: a grade 4 neutropenia lasting longer than 7 days, a grade 4 thrombocytopenia, a neutropenic fever, or a grade 3 or above non-hematological toxicity except for nausea, vomiting and alopecia; a grade 3 or above nausea, vomiting or diarrhea is considered as DLT only if still observed after treatment. Please refer to dose escalation diagram to conduct dose escalation trial. 