Inclusion Criteria:

1. Histologically confirmed mucosal or acral 2. Presence of a c-Kit mutation of exon 9, 11 or 13, or mutations Y822D and mutations D820Y, Y823D of exon 17, as confirmed by the central laboratory 3. Stage III unresectable or stage IV disease 4. The presence of one or more measurable lesions as detected by radiological or photographic methods and assessed according to RECIST 1.0. Lesions must have a size of at least 10mm at longest diameter (using a slice thickness of 5 mm)or double the slice thickness to be considered a target lesion. Target lesions should not be selected in previously irradiated fields unless there is clear evidence of progression 5. WHO performance status 0 - 2

Exclusion Criteria:

1. C-Kit mutation of exons 17(except mutations D820Y, Y822D or Y823D) or any other exon not allowed by the inclusion criteria
2. Patients with c-Kit amplifications only and no mutation
3. Patients with any history of brain metastases
4. Patients who have had any prior treatment with TKIs
5. Patients receiving medications or herbal extracts which interfere with nilotinib metabolism which are not discontinued by the time of the baseline visit

Other protocol-defined inclusion/exclusion criteria may apply.