The objective is to compare efficacy and safety of masitinib at 12 mg/kg/day to sunitinib at 50 mg/day in treatment of patients with gastro-intestinal stromal tumor resistant to imatinib.

Inclusion Criteria:

1. Histological proven, metastatic, or locally advanced and non-operable GIST
2. Measurable tumor lesions with longest diameter ≥ 20 mm using conventional techniques or ≥ 10 mm with spiral CT scan according RECIST criteria
3. C-kit (CD117) positive tumors detected immuno-histochemically and documented mutation of c-kit at any time if available
4. Patients resistant to imatinib at dose of 400 mg/day

Exclusion Criteria:

1. Patient treated for a cancer other than GIST cancer within 5 years before enrolment, with the exception of basal cell carcinoma or cervical cancer in situ
2. Patient with active central nervous system (CNS) metastasis or with history of CNS metastasis