Inclusion Criteria:

Phase l:

- Patients aged ≥ 18 years

- Patients with a histologically proven diagnosis of GIST and clinical evidence of
resistance to imatinib despite at least 4 months continuous treatment with imatinib

- Patients with at least 2 months at a dosage of ≥ 600 mg/day (progression despite
uninterrupted therapy for 2 months at ≥800 mg/d for patients entering the Phase I
cohort investigating the 800 mg/d dose)

- Patients were to have at least one measurable lesion (longest diameter ≥20 mm on
conventional CT or MRI scan

- patients were to have ≥10 mm on spiral CT) and were to have a WHO Performance Status
Score ≤ 2.

- Patients also were to have adequate bone marrow, liver and renal function on imatinib
treatment, as specified in the protocol

Phase ll:

• For Phase II (Stratum 2) patients must have progression on other 2nd line drug therapies
following prior progression on imatinib (Stratum 2)

Exclusion Criteria:

- Women who are pregnant or breast-feeding

- Patients presenting with known or symptomatic CNS metastases or leptomeningeal
involvement

- Patients with any concurrent major medical condition liable to compromise the
patient's participation in the study (e.g. known HIV infection, uncontrolled
diabetes, serious cardiac dysrhythmia or condition, New York Heart Association
classification of III or IV, congestive cardiac failure, myocardial infarction with 6
months, unstable angina, chronic or acute renal or liver disease, uncontrolled
infections including abscess or fistulae, etc.)

- Patients with a history of another malignancy within 5 years prior to study entry,
except curatively treated non-melanotic skin cancer or in-situ cervical cancer

- Patients unwilling to or unable to comply with the protocol

- Patients who are receiving glucocorticoids (only if the p70s6 kinase1 assay is being
performed), since these have been shown to inhibit p70s6 kinase1 activity.

Other protocol-defined inclusion/exclusion criteria may apply