Molecular Imaging

PET/CT Product

ATA-1 (an Enlyton licensed anti-TAG-72 antibody fragment coupled with I-124)

Enlyton has identified an antibody fragment that promises to improve PET/CT imaging by more accurately reflecting the extent of cancerous tissues seen on imaging. ATA-1 is a proprietary anti-TAG-72 antibody fragment coupled with iodine-124 (124I). Enlyton’s antibody is a complimentary determining region (CDR)-grafted humanized domain-deleted anti-TAG-72 monoclonal antibody.  ATA-1 specifically targets the tumor-associated antigen, TAG-72, a mucin-like glycoprotein that is overexpressed by human adenocarcinomas and other disease-associated tissues. ATA-1 binds to early-stage and late-stage adenocarcimonas, as well as to cancer-bearing lymph nodes.

Previous clinical studies have demonstrated that anti-TAG-72 antibodies (i.e., B72.3, , murine CC49, humanized CC49, and HuCC49DeltaCH2), are safe and effective prognostic tools for the detection of adenocarcinomas.

ATA-1 will be Enlyton’s first product for imaging and is slated for PET/CT imaging clinical trials in early 2013.

The Problem That ATA-1 Addresses:

Currently, CT and 18F-FDG-based PET/CT scans are the primary methods of imaging used in oncology today.

As a first-line approach, CT scans are used to attempt to demonstrate tumor-related abnormalities when patients are first evaluated and diagnosed. However, CT scans may only be helpful when tumors reach a detectable finite size and may offer little use in determining the effects of ongoing cancer therapies.

In this regard, PET/CT imaging technology offers much more promise to improving cancer diagnosis, management, and monitoring strategies in oncology.

However, nearly all PET/CT procedures that are performed at the current time involve the use of 18F-FDG. 18F-FDG is not a cancer-specific targeting agent. Instead, 18F-FDG works based on the principle of recognizing elevated sugar metabolism within cancerous tissues. Resultantly, many tissues and organs of the body that normally metabolize high amounts of sugar are inadvertently visualized on 18F-FDG-based PET imaging (i.e., brain, heart, muscle, and bowel). Similarly, inflammatory, infectious, and post-surgical conditions are also inadvertently visualized. Therefore, from an oncology standpoint, 18F-FDG-based PET imaging is confounded by all of this non-specific and non-cancer related activity, thus making images difficult to interpret. In short, 18F-FDG-based PET imaging often fails to provide the physician with accurate information concerning the full extent of disease related to the patient’s malignancy.

ATA-1 addresses this problem by combining the potential advantages of PET/CT imaging technology with cancer-specific targeting capabilities.

Future Imaging Products:

It is expected that additional applications of Enlyton anti-TAG-72 antibodies will be employed in PET/MRI, SPECT/CT, and other imaging modalities.