Treatment of Newly Diagnosed Rhabdomyosarcoma Using Molecular Risk Stratification and Liposomal Irinotecan Based Therapy in Children With Intermediate and High Risk Disease

This is a phase II study to determine safety and efficacy of combining liposomal irinotecan with vincristine alternating with VAC in intermediate-risk patients, liposomal irinotecan with temozolomide and vincristine alternating with VAC in high-risk patients and the chemotherapy combinations when given with concomitant radiation therapy in intermediate and high risk patients. The dose of liposomal irinotecan for intermediate and high risk patients will be 160/mg/m2 on Day 1 based on the results and recommended phase 2 dose of the Phase I trial ONITT trial. The primary objective is to assess event-free survival (EFS). The sample size is determined based on a 2-year EFS estimate for each risk group, with a total study duration of 4 years for enrollment and 2 years of follow-up per patient. The study employs a single-arm adaptive Phase II design, with an estimated 46 patients in the intermediate-risk group and 34 patients in the high-risk group, ensuring 80% power and a 5% Type I error rate. The trial will conclude once the last enrolled patient has completed 2 years of follow-up.