For each cohort a two-stage design will be implemented. In the situation where expected accrual allows for a sufficient number of patients to be accrued, the alpha and beta errors will be fixed at 10%. However, in very rare diseases, such as inflammatory myofibroblastic tumor (IMT), neuroblastoma, glioblastoma, and rhabdomyosarcoma (RMS), it is anticipated that the target number may not be achievable in a reasonable timeframe; for these cohorts, the alpha and beta errors will be fixed at 15%. Consequently three different statistical designs will be a priori considered according to the expected response rate and incidence.