Multicenter phase I/II trial of topotecan (T) and ifosfamide (I) combination as second-line therapy for pediatric solid cancer: Phase II results.

10050 Background: Both of T and I are key drugs for recurrent pediatric solid malignancies but rarely used in combination. Results of the phase I portion of the combination of T and I chemotherapy (TI) which is dose-finding study by CRM method in ASCO 2010. We hereby report the results of efficacy and safety screening of TI conducted as a phase II portion. Methods: Recurrent pediatric solid malignancies with history of chemotherapy no more than 20 cycles (Cs) are eligible. Combination of I (1.2g/m2/day) and T (0.6 mg/m2/day) were administered day 1 through 5 up to six Cs. In the phase II portion, a Simon optimal two-stage design was adopted using treatment compliance with 4 Cs of TI as primary endpoint. Unacceptable compliance was set at 20% and promising one at 40%. If more than two patients (pts) among initial 13-15 pts successfully complete 4 Cs, patients’ enrollment is allowed to continue until a total of 33 pts in the phase II portion. Complete or Partial Response (CR+PR) was evaluated according to R...