Avid Bioservices Inc (CDMO)

[freethemice]

As far as I can tell there is only one FDA approved radioisotope-antibody for imaging cancer
that is still available. That is ProstaScint, made by Cytogen.

Here is a good paper to start with.
ImmunoPET In Cancer Models
Seminars in Nuclear Medicine, May 2010; 40(3):182-189
It is freely available here:
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC2848398/?tool=pubmed

They give a good amount of discussion of bavituximab and the radioisotope 74As.

"It is important to note that the vast majority of tumor targeting properties described for
engineered antibody fragments, and how they relate to their behavior as immunoPET
radiotracers, have been defined in the context of binding to antigens present on the surface of
cells in solid tumor models of cancer (25). Antigens found on the surface of tumor vasculature
represent an additional set of targets that can be exploited for immunoPET imaging. Access of
antibodies to these antigens is not subject to the physical barriers associated with targeting
tumor cell antigens. Phosphatidylserine (PS) is normally tightly segregated to the internal
leaflet of the plasma membrane. This asymmetry is lost on tumor vascular endothelium,
exposing PS on the surface of the endothelial cells. This restricted expression of PS has been
exploited for development of the anti-PS mAb bavituximab (40). Bavituximab, when labeled
with the positron emitting radioisotope 74As (t½ = 17.8 days, 29% ß+,128 keV) was able to
effectively localize to tumor vasculature. At 72 hours post-injection, 74As-bavituximab
achieved a 22:1 tumor-to-liver ratio in a rat model of prostate cancer. This compared very
favorably with the 1.5:1 ratio seen with an isotype-matched control antibody and resulted in
effective tumor imaging. PS is exposed on the vasculature of a wide variety of solid tumors,
suggesting that bavituximab, or engineered fragments based on its variable domains, have the
potential to be effective immunoPET tracers for a broad range of diseases. The potential utility
of vasculature imaging is underscored by the increasing use of anti-angiogenic therapies (e.g.
bevacizumab)."