Our technology allows us to create companion imaging diagnostics intended for use with each of our SMDCs. To create our companion imaging diagnostics, we replace the drug payload of the SMDC with an imaging agent that is easily seen with widely available nuclear imaging equipment. Because the targeting ligand found on the companion imaging diagnostic is identical to that found on the therapeutic SMDC, our companion imaging diagnostics allow us to obtain full-body real-time images of tumors that over-express the target for that particular SMDC. This is accomplished without requiring an invasive tissue biopsy or reliance on archived tissue samples.

The information provided by our companion imaging diagnostics is used throughout the development of every new SMDC. In both preclinical and clinical trials, a companion imaging diagnostic is used to validate targeting of our SMDC to specific tissues and cells. These companion imaging diagnostics also allow for the screening of large patient populations to select diseases where a high percentage of the patient population have tumors or diseased cells that over-express the molecular target. These companion imaging diagnostics may also enable us to expand the use of our SMDCs to cancer indications where the percentage of patients who over-express a given receptor target of interest may be relatively low and help to identify patients who will most likely benefit from treatment with our SMDCs.

These powerful companion diagnostics are being used in all of our trials to identify the most appropriate patient population for clinical testing. The diagnostic images below were obtained following administration of our folate-receptor targeted imaging agent EC20-Tc99m. The patient on the left shows no targeting to tumor (negative profile). The patient on the right shows targeting to tumors (positive profile).