The study consists of 2 cohorts:~Cohort 1 (Traditional chemotherapy) will evaluate the efficacy of ifosfamide and etoposide in children, adolescents, and young adults with relapsed or refractory osteosarcoma.~Cohort 2 (Combination Expansion) will evaluate the efficacy of Sulfatinib in combination with ifosfamide and etoposide in children, adolescents, and young adults with relapsed or refractory osteosarcoma.~Sulfatinib will be provided as hard capsules containing 300 mg Sulfatinib. Sulfatinib capsules should be dissolved in water or apple juice for those who are unable to swallow capsules.
This is a phase 1/2 study evaluating safety, tolerability, and efficacy of Sulfatinib in combination with chemotherapy (ifosfamide and etoposide) in children and adolescents with refractory or relapsed osteosarcoma ( combination Sulfatinib).