Phase II study of ifosfamide as a single drug for relapsed paediatric patients.

A total of 22 patients with different solid tumours refractory to previous chemotherapy were treated between May 1985 and December 1986 (osteosarcoma, 7; Wilms' tumour, 6; rhabdomyosarcoma, 2; Ewing's sarcoma, 2; non-Hodgkin's lymphoma, 2; retinoblastoma, 1; cavum lymphoepithelioma, 1; dyktioma, 1). Patients were aged between 3 and 20 years (mean, 10.6 years). There was a 3.4:1 male-to-female ratio. The treatment consisted of ifosfamide given i.v. as a single agent at a dose of 3,000 mg/m2 over 1 h on days 1 and 2. Mesna was given as a uroprotector at 600 mg/m2 every 4 h, up to a total of 13 doses. The courses were repeated every 3 weeks. Every patient except those with osteosarcoma had previously received cyclophosphamide. There were 3 (13.6%) complete responses (CRs) in 2 osteosarcomas and 1 abdominal non-Hodgkin's lymphoma, lasting 12, 8 and 2 months, respectively; 4 (18.2%) partial responses (PRs) in 2 Wilms' tumours, 1 Ewing's sarcoma and 1 abdominal non-Hodgkin's lymphoma; 4 absences of remission (ARs); and 11 (50%) cases of progressive disease (PD). In all, 81 courses were given, and the toxicities found were leukopenia (less than 2,000 leukocytes) in 15 courses, thrombocytopenia in 3, microhaematuria in 7, neurotoxicity in 8, fever in 8 and hypertension in 2. The overall response rate (31.8%) was encouraging and the toxicity, acceptable and reversible. These results demonstrate that ifosfamide should be considered for introduction into phase III protocols for the treatment of solid malignancies in children.