A Phase II "Up-Front Window Study" of Irinotecan (CPT-11) Followed by Multimodal, Multiagent, Therapy for Selected Children and Adolescents With Newly Diagnosed Stage 4/Clinical Group IV Rhabdomyosarcoma: An IRS-V Study

OBJECTIVES:

• Determine the response rate of patients with newly diagnosed high-risk metastatic stage IV/clinical group IV rhabdomyosarcoma treated with upfront window therapy comprising irinotecan and vincristine.
• Determine the toxic effects of this regimen in these patients.
• Determine the toxic effects of this regimen when given in alternating courses with vincristine, dactinomycin, and cyclophosphamide (VAC) as continuation therapy in patients with partial or complete response.
• Determine the overall and failure-free survival of patients treated with irinotecan and vincristine followed by VAC alone or VAC alternating with vincristine and irinotecan plus radiotherapy.
• Determine the pharmacokinetics of irinotecan and vincristine in these patients.

OUTLINE:

• Upfront window therapy: Patients receive vincristine IV on days 1 and 8 and irinotecan IV over 60 minutes on days 1-5 and 8-12. Treatment repeats every 21 days for a total of 2 courses. Patients experiencing partial or complete response proceed to regimen A. Patients experiencing stable or progressive disease proceed to regimen B.

• Regimen A: Patients receive vincristine IV over 1 minute weekly on weeks 6-13, 15-19, 23-27, 29, 32-35, 38-39, and 41; dactinomycin IV over 1 minute weekly on weeks 6, 12, 23, 29, 35, and 41; and cyclophosphamide IV over 30-60 minutes weekly on weeks 6, 12, 16, 19, 23, 29, 35, and 41. Patients also receive irinotecan IV over 1 hour daily, 5 days a week, on weeks 9, 10, 26, 27, 32, 33, 38, and 39 and undergo radiotherapy daily, 5 days a week, on weeks 15-22.

• Regimen B: Patients receive vincristine as in regimen A; dactinomycin IV over 1 minute weekly on weeks 6, 9, 12, 23, 26, 29, 32, 35, 38, and 41 and cyclophosphamide IV over 30-60 minutes weekly on weeks 6, 9, 12, 16, 19, 23, 26, 29, 32, 35, 38, and 41. Patients receive radiotherapy as in regimen A.