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The objective of this study is to determine the efficacy and safety of SUTENT in patients with recurrent or progressive glioblastoma multiforme.Patients with tissue based diagnosis of intracranial glioblastoma multiforme, above 18 years of age and of both genders, who have a first tumor recurrence or progress after surgery, radiation- and chemotherapy will be included. The hypothesis is that SUTENT will significantly increase the progression free survival rate at 6 months in the study population.
Full description
Background Glioblastoma multiforme (GBM) is the most common and most aggressive primary brain tumor in adults and shows an incidence of 5/100.000 inhabitants per year1. In Austria, approximately 350 patients are diagnosed with malignant glioma annually. Advances in surgery, radiotherapy and chemotherapy do only have a minor impact on the natural course of these hardly treatable tumors. The mean survival time of adult patients with GBM is only 9-15 months from the time of diagnosis1,2. Thus, there is an urgent need for more effective therapeutic approaches based on a better molecular understanding of tumor progression and tumor neovascularization.
Molecular Neurooncology has begun to elucidate the complexity of the transformed phenotype of GBM with the goal to identify important molecular changes in the tumor cell that may be amenable for targeted therapies3.
The elucidation of growth factor receptor signaling pathways responsible for the malignant phenotype is now being translated into molecular therapies. At present, targeted therapies with small molecule inhibitors directed against receptor tyrosine kinases (RTKs) or downstream signaling pathways seem to be the most promising therapeutic approaches by directly influencing oncogenetically altered signaling pathways4. Imatinib Mesylate (STI571, Gleevec) is a potent inhibitor of the Bcr-Abl, PDGFR-α/ß, c-Fms and c-KIT tyrosine kinases. Its ability to inhibit PDGFR signaling suggested therapeutic potential in malignant gliomas, but single-agent imatinib showed only minimal therapeutic activity5. Erlotinib (OSI-774, Tarceva) and Gefitinib (ZD1839, Iressa) are potent inhibitors of the Epidermal-Growth-Factor-Receptor (EGFR). However, both inhibitors have also demonstrated only limited activity in GBMs with response rates of 10 to 15% and no significant prolongation of survival6. Tipifarnib (R115777, Zarnestra) is a potent and selective inhibitor of the farnesyl-transferase and influences the Ras oncogene pathway. Overexpression of Ras is implicated in the pathogenesis of malignant gliomas, but also amplified receptors as EGFR, PDGFR and VEGFR can lead to its downstream activation. Clinical trials with inhibition of the Ras signaling pathway showed also only limited biologic effects in GBM patients7.
3.2. Rationale for SUTENT treatment of GBM Patients Reason for the limited activity of selective targeting single agents, but also chemotherapeutic treatments, in GBM patients is the heterogeneity and redundancy of the molecular pathways in glioma cells8. Therefore, a multi-targeted therapy approach, inhibiting multiple molecular signaling pathways involved in tumor progression and tumor neovascularization seems to be a more promising treatment strategy.
SUTENT (SUNITINIB, SU11248) is a potent multi-target inhibitor of VEGFR1-3, PDGFR-α/β, FLT3, c-KIT, RET and CSF-1R. This drug has shown good solubility, bioavailability and protein-binding characteristics9 and was highly effective in metastatic clear-cell renal cell carcinoma (MRCC)10-12 and gastrointestinal stromal tumor (GIST)13,14.
The aggressiveness of GBM is reflected by a diffuse local infiltration into the brain parenchyma and a high tumor vascularization15,16. Neuropathological hallmarks of GBMs are pseudopalisades and microvascular hyperplasia. Pseudopalisades are characterized by an accumulation of hypoxic tumor cells around a central necrosis (Fig. 3A), resulting from increased metabolic demands of tumor cells or vascular occlusion. Such tumor cells express high levels of hypoxia-inducible regulators of angiogenesis, including the hypoxia-inducible factor (HIF)-α. HIF-α accumulates in the tumor cell and binds with its constitutively present partner HIF-β. The HIF complex leads to transcription of hypoxia-induced genes, such as VEGF and PDGF17. These growth factors are secreted into the extracellular space by tumor cells and bind to its high-affinity receptors located on
Therefore, VEGF may induce microvascular hyperplasia (Fig. 1B), a typical form of neoangiogenesis immediately related to pseudopalisading cells16,22. Since necrosis and hypoxia are located in the GBM's core, the most biologically relevant hypoxia-induced neovascularization occurs further peripherally, favouring diffuse infiltration by individual glioma cells and allows peripheral GBM expansion.
Summary of molecular and clinical rationales for SUTENT treatment of GBM patients
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Inclusion criteria
Bone Marrow Reserve - Platelets ≥ 75.000/μL
Exclusion criteria
The patient is active participant in another clinical trial.
Exclusion of patients in the event of
Significant Co-Morbidities within 12 months prior to study enrollment
Significant Co-Morbidities at Baseline Evaluation
Anticoagulation: Current treatment with therapeutic doses of Marcoumar / Sintrom excluding thrombosis prophylaxis with low dose Heparin.
Antiepileptic Drugs: Concurrent use of EIADs within 2 weeks of study enrollment (patients must discontinue EIAD treatment ≥ 14 days prior to study enrollment)
Pregnancy, Breastfeeding and Non-Contraception
Evidence of increased intracranial pressure
Other severe acute or chronic medical or psychiatric condition or laboratory abnormality that would impart excess risk associated with study participation or study drug administration, or which would make the patient inappropriate for entry into this study. The decision to enroll the patient in this study is in the judgment of the investigator.
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70 participants in 1 patient group
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Data sourced from clinicaltrials.gov
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