Inclusion Criteria:

• Histologically confirmed diagnosis of GIST that is unresectable and/or metastatic
• Radiological confirmation of disease progression or intolerance to imatinib therapy at a any dose
• At least one measurable site of disease on CT scan at Visit-2
• WHO Performance Status of 0, 1 or 2 at Visit-2
• Patients must have normal organ, electrolyte, and marrow function at Visit-1 and Visit-2

Exclusion Criteria:

• Prior treatment with nilotinib or any other tyrosine kinase inhibitors except imatinib.
• Treatment with any cytotoxic and/or investigational cytotoxic drug ≤ 4 weeks
• Prior or concomitant malignancies other than GIST
• Impaired cardiac function at Visit-1 or 2
• Patients with severe and/or uncontrolled concurrent medical disease
• Use of therapeutic coumarin derivatives
• Use of any medications that prolong the QT interval
• Use of CYP3A4 inhibitors
• Patients who have undergone major surgery ≤ 2 weeks prior to Visit-1 or who have not recovered from side effects of such surgery
• Patients who have received wide field radiotherapy ≤ 4 weeks or limited field radiation for palliation < 2 weeks prior to Visit-1 or who have not recovered from side effects of such therapy

Other protocol-defined inclusion/exclusion criteria may apply