Phase Ib Study of SUnitinib Alternating With REgorafenib in Patients With Metastatic and/or Unresectable GIST

Intervention Description: 3 days of once daily sunitinib alternating with 4 days of once daily regorafenib throughout each 28 day cycle. The starting dose level (level 1) is sunitinib 37.5 mg/d and regorafenib 120 mg/d, and doses will be escalated in subsequent cohorts following a classical 3+3 design up to sunitinib 50 mg/d and regorafenib 160 mg/d or until maximum tolerable dosage (MTD) and recommended phase II dose (RP2D) is determined. Number of Cycles: until progression or unacceptable toxicity develops.

Intervention Description: 3 days of once daily sunitinib alternating with 4 days of once daily regorafenib throughout each 28 day cycle. The starting dose level (level 1) is sunitinib 37.5 mg/d and regorafenib 120 mg/d, and doses will be escalated in subsequent cohorts following a classical 3+3 design up to sunitinib 50 mg/d and regorafenib 160 mg/d or until maximum tolerable dosage (MTD) and recommended phase II dose (RP2D) is determined. Number of Cycles: until progression or unacceptable toxicity develops.