This research study is a clinical trial of a new combination of drugs as a possible treatment
for relapsed/refractory Ewing sarcoma and/or osteosarcoma.
- The names of the drugs are:
- Cabozantinib
- Topotecan
- Cyclophosphamide
- The names of the non-investigational supportive care drugs are:
- Filgrastim, pegfilgrastim, or a related growth factor.