Netherlands Radiolabeled Bevacizumab Trial

In the age of molecularly-targeted chemotherapy, diffuse intrinsic pontine gliomas are tough tumors.  DIPGs seem to be molecularly heterogenous tumors- not only between individuals but also within a single tumor.  If one can not obtain tissue then it is impossible to know if a particular tumor even has the target.  And if one does get a biopsy the concern is is really representative?

There is also the concern perhaps the brainstem is more difficult to get agents in- is the blood brain barrier just more tight in that area?

For me the question has been, how do we address these concerns clinically?  It appear that the researchers at VU University Medical Center in the Netherlands are trying to look at these questions by using an immuno-PET approach.

Immuno-PET scanning  uses a radio-labeled monoclonoal antibody.   The idea is that the radio-labeled agent will stick at the place where there is the specific receptor and the tag will let it light up on the scan.   One could think of it as "a comprehensive immunohistochemical stain in vivo".    In this case the monoclonal antibody bevacizumab is labeled with 89Zr.  PET scans will be done at 1, 72 and 144 hours after administration.

Immuno-PET looks like a  novel way to get answers to some of these questions.  My hope is that this study will provide new knowledge on drug distribution with a anti-VEGF in DIPG.   Since pediatric high grade gliomas are also included it will be interesting to compare these two different populations.

This research has been supported by Stichting Semmy.

Reference:
Determining the tumor uptake of labelled bevacizumab in children with high grade or diffuse intrinsic pontine glioma on PET Scans
http://www.trialregister.nl/trialreg/admin/rctview.asp?TC=3518

Immuno-PET: a navigator in monoclonal antibody development and applications.
Full Text-http://theoncologist.alphamedpress.org/content/12/12/1379.long