A Phase I Dose Finding Study in Children With Solid Tumors Recurrent or Refractory to Standard Therapy

Dose escalation phase of the study : To define the safety profile, maximum tolerated dose (MTD) and recommended phase II dose (RP2D) of regorafenib administered orally as a single agent in a 3-weeks-on/1- week-off schedule in repeating cycles of 28 days in pediatric subjects with solid malignant tumors recurrent or refractory to standard therapy. To characterize the pharmacokinetics (PK) of regorafenib The dose escalation phase of the study has been completed. Expansion phase: To define the safety profile, MTD and the RP2D of regorafenib administered orally in combination with backbone chemotherapy (vincristine and irinotecan) at relapse in pediatric subjects with rhabdomyosarcoma (RMS) and other solid malignant tumors recurrent or refractory to standard therapy.