Noninvasive Brain Imaging for Experimental Medicine in Drug Discovery and Development

Abstract

There is currently increased focus on experimental medicine in drug development. Imaging methods potentially provide highly cost-effective, general approaches for the noninvasive characterisation of disease and pharmacokinetics, pharmacodynamics and drug effects directly in humans in ways that can enable this. The two methods most widely employed now are positron emission tomography (PET) and magnetic resonance imaging (MRI). PET allows the distribution of radiolabelled molecules to be mapped, enabling studies of molecule distribution and tissue metabolism. MRI was initially used primarily to define tissue structure, but a more recent range of functional MRI techniques promise the potential to define pharmacokinetic data over biologically meaningful timescales. With an understanding of the relationship between imaging biomarker changes and clinical outcomes, imaging can be used as a surrogate marker of response even for the later stages of drug development.