Regorafenib in Patients With Refractory Primary Bone Tumors

Patients will receive regorafenib orally at doses adjusted for age, body surface area and pharmacokinetics. Treatment with regorafenib will be continued for up to 1 year or until disease progression, patient death, unacceptable toxicity, or study closure. Pharmacokinetics and safety profile of the investigational product (IP) will be determined throughout the course therapy. In the event of progression or relapse, patients in the control group will have the option to receive the IP along with the standard treatment of the next line.