[High dose ifosfamide at 15 g/m2/cycle: a feasibility study in 10 patients]

Ifosfamide is one of the most efficient antimitotic in soft tissue sarcoma. To try to find a possible dose-effect, 10 patients with advanced pretraited relapsed soft tissue sarcoma received 15 g/m2/cycle ifosfamide in continuous infusion during 5 days. A pharmacokinetic study was done for 2 patients. All patients received growth factors, ondansetron and 8 clonazepam. Renal toxicity was evaluated after the first and the second cycle. Twenty two cycles were delivered to patients who have been already treated with ifosfamid (10 patients with 15 g/m2 to 54 g/m2, median 27 g/m2) or cis platinum (2 patients). No major renal or neurologic toxicity was observed; only subclinical modifications of urinary enzymes excretion were found. Two patients had visual hallucinations at the end of a cycle and just in the 2 following days; another presented a neuropathy of inferior limbs. Hematological toxicity was very limited. Pharmacokinetic study did not show induction mechanism at this dosage and with this type of administration. So ifosfamide 3 g/m2 during 5 days is feasible. The few level of complications observed is perhaps linked to the daily dose of 3 g/m2 instead of 4 g/m2 or more used in the other studies.