A phase II window study of irinotecan (CPT-11) in high risk Ewing sarcoma: a Euro-E.W.I.N.G. study.

BACKGROUND The prognosis for patients with nonpulmonary metastatic Ewing sarcoma remains poor with survival in the order of 15-20%. The need to introduce effective new agents into clinical practice is clear. Based on a preclinical rationale of responses in xenografts and backed by a phase I study in children, the Euro-E.W.I.N.G consortium planned a phase II window study of irinotecan in newly diagnosed high risk metastatic patients with Ewing sarcoma. PROCEDURES Patients were recruited between April 2004 and December 2007. Two courses of irinotecan were administered at a dose of 600 mg/m(2) as a 1 hour infusion at 21 day intervals. Response evaluation was determined after the second course of treatment by radiological assessment of primary and metastatic sites and, where appropriate bone marrow sampling. RESULTS Twenty-three patients were recruited. Two patients were deemed inevaluable for response. Five patients (24%) demonstrated a partial response. Grade 3 or 4 diarrhoea was seen in 4/43 course of treatment and was managed with loperamide. CONCLUSIONS This is the first report of single agent irinotecan activity in an untreated population of patients with Ewing sarcoma. In common with other paediatric tumours and other camptothecin analogues such as topotecan, single agent activity is only modest. The exact role for the use of irinotecan in patients with ES, dose schedule and combinations with other agents still requires further investigation.