Purpose : The objective of this study was to determine the tolerance and toxicities of high-dose cyclophosphamide (CPA) at 7 g/m 2 given in four fractions over 8 h in children with advanced solid tumors. Patients and Methods : Twenty children aged 1 1/2-19 years (median, 12 years) received 24 courses of high-dose CPA at 7 g/m 2 for the treatment of advanced malignant solid tumor. CPA was given in four 1-h infusions of 1.75 g/m 2 each, with 1 h of rest between each dose. MESNA was used as a uroprotective agent and was continued for 24 h after the final dose of CPA. With only one exception, all patients were discharged at the end of MESNA infusion and received granulocyte colony-stimulating factor, prophylactic ciprofloxacin, and co-trimoxazole. Results : Severe but transient myelosuppression was observed. The median time to neutrophil and platelet recovery was 17 and 19 days, respectively. Fever developed after 13 of the 24 courses, and hospitalization was required. Extramedullary toxicities were mild. No patient showed cardiomyopathy or hemorrhagic cystitis. Forty-six percent of the courses were managed entirely on an outpatient basis. Objective tumor response was seen in five patients. Conclusions : CPA at 7 g/m 2 is well tolerated by children with advanced malignancies and should be considered in earlier phases of antineoplastic therapy.
