Imatinib Mesylate in Patients With Refractory Desmoplastic Small Round Cell Tumors

Inclusion criteria: 1. Patients \> 16 years of age. 2. Histologically documented diagnosis of DSRCT, unresponsive or in no complete remission after any conventional multimodality approach. 3. Immunohistochemical documentation of activated PDGF-R expression by tumor 4. At least one measurable site of disease 5. Performance status 0,1, 2 or 3 (Eastern Cooperative Oncology Group) 6. Adequate end organ function Exclusion criteria: 1. Patient has received any other investigational agents within 28 days of first day of study drug dosing, unless the disease is rapidly progressing. 2. Patient is \< 5 years free of another primary malignancy 3. Patient with congestive heart failure or myocardial infarction within 6 months of study 4. Female patients who are pregnant or breast-feeding. 5. Severe and/or uncontrolled medical disease 6. Known brain metastasis. 7. Chronic active hepatitis or cirrhosis 8. Known diagnosis of human immunodeficiency virus (HIV) infection. 9. Chemotherapy within 4 weeks prior to study entry, unless the disease is rapidly progressing. 10. Previous radiotherapy to \> 25 % of the bone marrow 11. Major surgery within 2 weeks prior to study entry. Other protocol defined inclusion/exclusion criteria may apply.