The combination of ifosfamide and irinotecan was tested in a dose-finding study. The preliminary results of the combination in this phase I study did not show any major toxicity that could help to define the dose-limiting toxicity. The escalation continues even after nine levels; the study is therefore ongoing. The main toxicity is gastrointestinal, with mild nausea, vomiting, and diarrhea. There was some other irrelevant toxicity, which was easily manageable with the usual supportive therapy. When responses were evaluated, stable disease was found in some cases, suggesting some activity for the combination.