Efficacy of Regorafenib Combined With Best Supportive Care as Maintenance Treatment in High Grade Bone Sarcomas Patients

This is a multicenter phase II study concerning patients with high-grade bone sarcoma (HGBS) without complete remission after standard treatment at diagnosis or at relapse. Patients will be treated with regorafenib + best supportive care (BSC) for a maximum of 12 months as maintenance therapy after standard line therapy completion. Progression free rate (PFR) data will be collected and analysed for all included patients to evaluate if regorafenib + BSC can be considered as an interesting treatment for further investigations in this indication.

This is a multicenter phase II study. Patients with evaluable unresectable residual disease will be accrued after they completed standard of care, consisting of: * At diagnosis: standard multimodal treatment based on histological subtype * At relapse: chemotherapy Patients who meet the eligibility criteria will receive regorafenib + best supportive care (BSC) as maintenance treatment for a maximum 12 months period. After their eligibility has been confirmed, patients will receive regorafenib until disease progression, or for a maximum of 12 months, or unacceptable toxicity or willingness to stop, whichever occurs first. After the completion of the maintenance therapy (12 months) patients will be followed-up until the first radiological disease progression, unless a premature disease progression occurred. All patients will be followed-up until the data cut-off (12 months after the last inclusion). The vital status will be updated once for all patients at 24 months after the last inclusion, based on patient's medical file.