White Paper: The Application Of Novel Imaging Methods To New Drug Development

By Bruce J. Hillman, MD, Chief Scientific Officer, ACR Image Metrix

Medical imaging is a powerful tool that is increasingly being employed in all phases of new drug development, from pre-clinical testing to advanced clinical trials. The purposes of using imaging methods in trials are several-fold: 1. to relatively non-invasively gain insights as to the mechanism of action of a drug in vivo; 2. to provide additional evidence that an early phase drug is active against the target condition; and 3. to serve as a primary or important secondary endpoint for a late phase, registrational clinical trial.

All of these applications are based on the assumption that the data derived from an imaging test reflects some physiological activity induced by the drug – that is to say that the imaging test serves as a biomarker. Using imaging as a biomarker is not a novel concept. The application of the RECIST or WHO criteria to measure changes in the dimensions of tumor masses as a metric of the effectiveness of anti-oncologic agents is perhaps the most familiar example. However, there are wellrecognized problems with employing traditional anatomic measurements, including high measurement variability, the often poor correlation between measurement endpoints and clinically important outcomes, and the long delay between drug administration and its impact on anatomical size.