Patients with advanced (unresectable and/or metastatic) GIST who failed after previous therapy involving both imatinib and sunitinib will be eligible. Failure to imatinib and sunitinib is defined as disease progression regardless of intervening response during therapy, or intolerance. There is no limit to the number of prior therapies a patient may have received (e.g., patients may have received therapy with nilotinib, other TKIs, or chemotherapy in addition to imatinib or sunitinib).