Open-label Trial of GlivecWith Unresectable or Metastatic Malignant Gastrointestinal Stromal Tumors

Inclusion Criteria: Patients >= 18 years of age Histologically documented diagnosis of GIST which is malignant as well as unresectable (=not amenable to surgery with curative intent) and/or metastatic and therefore incurable Immunohistochemical documentation of c-kit (CD117) expression by tumor At least one measurable site of disease (as defined by Southwestern Oncology Group Solid Tumor Response Criteria) which has not been previously embolised or irradiated Performance status 0,1, 2 or 3 (ECOG) Adequate end organ function, defined as the following: total bilirubin < 1.5 x ULN, SGOT and SGPT < 2.5 x UNL (or < 5 x ULN if hepatic metastases are present), creatinine < 1.5 x ULN, ANC > 1.5 x 109/L, platelets > 100 x 109/L Female patients of child-bearing potential must have negative pregnancy test within 7 days before initiation of study drug dosing. Post menopausal women must be amenorrheic for at least 12 months to be considered of non-childbearing potential. Male and female patients of reproductive potential must agree to employ an effective barrier method of birth control throughout the study and for up to 3 months following discontinuation of study drug Life expectancy of at least 6 months Written, voluntary, informed consent Patients who were previously treated with chemotherapy will be eligible for this study Patient who are at least 5 years free of melanoma will be eligible for this study Exclusion Criteria: Patient has received any other investigational agents within 28 days of first day of study drug dosing Patient is < 5 years free of another primary malignancy except: if the other primary malignancy is not currently clinically significant nor requiring active intervention and CECOGs' approval is obtained, or if other primary malignancy is a basal cell skin cancer or a cervical carcinoma in situ. Existence of any other malignant disease is not allowed Patient with Grade III/IV cardiac problems as defined by the New York Heart Association Criteria. (i.e., congestive heart failure, myocardial infarction within 6 months of study) Female patients who are pregnant or breast-feeding. Patient has a severe and/or uncontrolled medical disease (i.e., uncontrolled diabetes, chronic renal disease, or active uncontrolled infection) Patient has a known brain metastasis Patient has an acute or known chronic liver disease (i.e., chronic active hepatitis, cirrhosis) Patient has a known diagnosis of human immunodeficiency virus (HIV) infection Patient received chemotherapy within 4 weeks (6 weeks for nitrosoureas or mitomycin-C) prior to study entry Patient previously received radiotherapy to >= 25 % of the bone marrow Patient had a major surgery within 2 weeks prior to study entry Patient with any significant history of non-compliance to medical regimens or with inability to grant reliable informed consent Therapeutic anticoagulation with warfarin (e.g. Coumadin® or Coumadine®)