Study of ZD1839 Combined With Irinotecan and Vincristine in Pediatric Patients With Refractory Solid Tumors

Objectives of this study are: * To determine the dose-limiting toxicities (DLT) of the combination of irinotecan and ZD1839 when given on this schedule. * To characterize the pharmacokinetics and pharmacodynamics of gefitinib alone and in combination with irinotecan and vincristine. * To estimate the maximum tolerated dose (MTD) of gefitinib in combination with escalating intravenous irinotecan by using selective intestinal decontamination with oral cefixime or cefpodoxime to prevent diarrhea. * To estimate the MTD of vincristine (MTD) in combination with gefitinib and irinotecan. Details of Treatment Interventions First Cohort: Standard dose escalation, starting at ZD1839 150 mg/m2/day for 21 days in combination with irinotecan 15mg/m2/day on a daily x 5 for two consecutive week schedule. Dose-limiting diarrhea was seen in this cohort. ZD scheduled was reduced to 12 days. The first dose level (1a) consisted of ZD1839 112.5mg/m2/day for 12 days + irinotecan 15mg/m2/day daily x 5 x 2 and was found to be the MTD in this cohort. Second Cohort: Cefixime then added at 4 additional subjects were enrolled at dose level 1c, consisting of ZD1839 at 112mg/m2/day + irinotecan 20mg/m2/day + cefixime 8 mg/kg/day administered once daily, beginning on day -1, and continued to day 14. Third Cohort: Irinotecan/ZD1839/Vincristine/Cefixime- Cefixime 8 mg/kg/day administered once daily, beginning on day -1, and continued to day 14, with a maximum dose of 400 mg daily + gefitinib 112.5 mg/m2 orally, daily for 12 days and irinotecan at 15 mg/m2 daily x 5 x 2 +1 mg/m2 (maximum 2mg/dose) on days 1 and 8 with escalating dose of VCR as tolerated.