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

Regorafenib will be given orally once a day, across cycles of 21 days each. During each cycle regorafenib is taken for 2 weeks followed by one week off the drug. Doses of the study drug used in this study are age-dependent and the children's dose will been adjusted based on the age and the body surface area and given either as tablets or granulate.

Vincristine will be given at a dose of 1.5 mg/m2 (0.05 mg/kg for subjects ≤ 10 kg, maximum 2.0 mg) on Day 1 and Day 8 in 21-day cycles.

Irinotecan will be administered at a starting dose of 50 mg/m2/day from Day 1 to Day 5, in 21 day cycles.