Study of Imatinib Mesylate in Combination With Hydroxyurea Versus Hydroxyurea Alone as an Oral Therapy in Patients With Temozolomide Resistant Progressive Glioblastoma

Inclusion Criteria: * Signed informed consent prior to initiation of any study procedure. * Patients \>= 18 years of age. * Histological confirmed diagnosis of glioblastoma multiforme / astrocytoma World Health Organization (WHO) grade IV by a reference pathologist * Eastern Cooperative Oncology Group (ECOG) Performance Status of 0, 1 or 2. * Adequate hepatic, renal and bone marrow function as defined by the following: total bilirubin \< 1.5 x Upper Limit of Normal (ULN), ALT and AST \< 2.5 x ULN, creatinine \< 1.5 x ULN, absolute neutrophil count \> 1.5 x109/L, platelets \> 100 x109/L and hemoglobin \> 10 g/dL. * Female patients of childbearing potential with a negative pregnancy test within 7 days of initiation of study drug dosing. Postmenopausal women must be amenorrheic for at least 12 months to be considered of non-childbearing potential. Male and female patients of reproductive potential who 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 \>3 months. * MRI available every 6 weeks for disease management * No intercerebral inflammation * Irradiation therapy 54 to 62 gy finished or less according to national standard * Chemotherapy at least 1 temozolomide containing regimen finished, no established chemotherapy regiment available and progression under chemotherapy or in between 6 months following the last chemotherapy. * Leucocytes \> 2.500/µl, to be controlled once a week * Thrombocytes \> 80.000/µl, to be controlled once a week * Ensured compliance * Patients who had a second or third resection after disease progression cannot be included earlier than 2 weeks following the resection. MRI should be performed not later than 72 h post operation. If patients are to be included later than 4 weeks after the resection, a new baseline MRI must be performed. Exclusion Criteria: * Female patients who are pregnant or breast-feeding. * Patients who have been treated with any investigational agent(s) within 28 days of the first day of administration of study drug. * Patients with uncontrolled medical disease such as diabetes mellitus, thyroid dysfunction, neuropsychiatric disorders, infection, angina or Grade 3 or 4 cardiac problems as defined by the New York Heart Association Criteria. * Patients with other malignant disorders. * Patient with acute or known chronic liver disease (i.e., chronic active hepatitis, cirrhosis). * Patients who are known to be HIV positive (no specific tests are required for confirmation of eligibility). * Expected incompliance according to treatment, treatment diary and examination schedule * Not confirmed histological diagnosis glioblastoma multiforme/astrocytoma WHO grade IV * Other drugs with potential cytostatic main or side effect * No or inadequate chemotherapy or irradiation therapy * Patients without hematological recovery after previous chemotherapy who have been treated with Chemotherapy within 28 days of the first day of administration of study drug. Other protocol-specific inclusion /exclusion criteria may apply.