Determining the tumor uptake of labelled bevacizumab in children with high grade or diffuse intrinsic pontine glioma on PET scans.

Paediatric high grade gliomas (pHGG) including diffuse intrinsic pontine gliomas (DIPG) have a poor prognosis. PET imaging with labelled antibodies enables drug distribution investigations and non-invasive target expression studies. pHGG and DIPG highly express vascular endothelial growth factor (VEGF) on RNA level, which is involved in mitogenic, angiogenic, and permeability enhancing processes. Monoclonal antibody bevacizumab inhibits VEGF-A and showed efficacy in adult glioma and to a lesser extend in pHGG. Bevacizumab is labelled to Zirconium-89, a positron emitter with a long half-time which is preferable because of its safety, purity and stable binding to its antibody and relatively low costs. In adults, 89Zr-bevacizumab could be used safely in humans and was shown to visualise targets precisely. In this study, bevacizumab is administered in a microdose at 1/100th of the therapeutic dose in pHGG and DIPG. PET scans are performed at 1, 72 and 144 hours post-injection. We expect that PET-imaging of 89Zr-bevacizumab may help to select patients more likely to respond to bevacizumab therapy.

Is there VEGF-expression in DIPG & HGG measured by the tumor uptake of Zr-bevacizumab?

89Zr-bevacizumab is injected and PET scans are performed at 1, 72 and 144 hours post-injection.

This is a diagnostic PET study. The labelled antibody is 89Zr-Bevacizumab.