Scientists have discovered that a combination of bevacizumab (Avastin) and radioactive copper-64 nuclide makes for an excellent imaging agent during PET/CT scanning.
From a press release by the The European Organization for Research and Treatment of Cancer (EORTC) , National Cancer Institute (NCI), and the American Assocation for Cancer Research (AACR):
Dr Zheng Jim Wang [Director of Molecular Imaging at MPI Research Inc (Michigan, USA) and an adjunct assistant professor at University of Texas Health Science Center at San Antonio] told the 20th EORTC-NCI-AACR  Symposium on Molecular Targets and Cancer Therapeutics in Geneva today (Wednesday 22 October) that he and his colleagues had attached bevacizumab to a molecule called DOTA (a cyclic compound) and tagged it with a radioactive tracer, Copper-64 (64Cu).
Bevacizumab is an antibody that targets vascular endothelial growth factor (VEGF), a signalling protein released by tumour cells and which plays an important role in angiogenesis (the process by which a growing tumour creates its own blood supply). Currently, bevacizumab is being used to treat patients with advanced colorectal cancer and is being tested in several other metastatic cancers.
When the researchers injected the compound (64Cu-bevacizumab) into mice with breast, lung and pancreatic cancers and then used PET/CT imaging to scan the animals, they found that it successfully targeted the cancer cells, accumulating in high concentrations in the tumours, and that it enabled clear and well-defined images of the tumours to be detected during scanning.
When compared with images of the same tumours in the same animals taken the day before, using the current gold standard imaging probe for tumours (18-Fluoro-Deoxy-Glucose (18FDG)), they found that not only were the 64Cu-bevacizumab images better, but also that they could detect tumours in earlier stages and at smaller sizes than with 18FDG. In addition, the 64Cu-bevacizumab images had none of the conventional “hot spots” that tend to appear in 18FDG images and which affect the accuracy of the imaging; “hot spots” occur where the compound has accumulated not just in tumours but also in key organs (such as the heart, brain, kidneys and bladder) which give false positive signals.
Press release: Researchers discover the anti-cancer drug bevacizumab can be used to detect and diagnose tumours in animal models using PET/CT imaging: results are better than current ‘gold standard’ method (PDF)