Avastin / Irinotecan in Patients With Recurrent or Progressive Malignant Glioma

Malignant glioma are the most common and aggressive primary brain tumors in adults. Despite advances in multimodal treatment including surgery, radiation and chemotherapy, most patients have a dismal prognosis of 9-15 months (Stupp et al., NEJM 2005). A major reason for the aggressiveness of malignant glioma is a pronounced tumor neovascularization, mainly driven by the vascular endothelial growth factor (VEGF) and its receptors. The therapeutic monoclonal antibody Bevacizumab (Avastin®) inhibits the VEGF pathway by binding the VEGF ligand. In Magnetic Resonance Imaging (MRI) this treatment reduces contrast enhancement by restoring both, the blood-brain-barrier and the destabilized vessel integrity. Furthermore, it raises the sensitivity of co-administered chemotherapeutics such as Irinotecan. In conclusion, anti-angiogenic therapy leads to the problem that the routinely used MRI techniques cannot distinguish anti-vascular effects from true anti-tumor effects. The study hypothesis of the clinical trial part is that in 35% of malignant glioma patients Avastin / Irinotecan chemotherapy results in objective tumor responses assessed by standard / functional MRI and FET- /FLT-PET neuroimaging. The study hypothesis for the translational study part is that the expression of the molecular targets of Avastin and Irinotecan in malignant glioma tissue ( = tumor and vascular cells) are predictive for Avastin / Irinotecan therapy induced treatment response measured by functional MRI and FET- / FLT-PET imaging.