Druggable targets and targeted drugs: enhancing the development of new therapeutics.

The advent of functional genomics, proteomics, chemi-informatics, and other systems-based scientific approaches have raised expectations of novel targets for drug discovery and design. Similarly, advances in materials sciences and biomolecular chemistries raised the prospects of highly targeted therapeutics that maximize efficacy while minimizing systemic toxicity. In spite of these advances, the gross measure of approvable drug output is declining, with only 17 new chemical entities approved by the FDA in 2007. This is in the face of high levels of R&D expenditures in both public and private sectors, and suggests that new, integrative approaches are needed in order to maximally exploit the rapidly expanding knowledge of potential drug and disease targets. The convergence of novel druggable targets with new chemical entities that can be specifically targeted to disease-causing sites and genes represents one means of creating highly efficacious and specific therapies. The approaches that are needed to facilitate such convergence include merging computational methods, systems biology, and gene-linked categorization of diseases with the use of appropriate drug delivery vehicles.