Systems Pharmacology, Drug-Target Networks
Relationships between drugs and their molecular targets can be characterized in a comprehensive manner using interaction networks.
For many years, the dominant approach of drug design has focused on the search for highly selective ligands targeting a specific disease-causing agent. However, this reductionist approach is now being questioned as many drugs are failing in late clinical development stages. It is estimated that as much as 30% of newly developed drugs fail due to a lack of efficacy and a similar rate due to harmful side effects (Hopkins 2008).
Systems biology has challenged this view by raising awareness that no component or process is isolated in biological systems. This principle applies to diseases as well, since many genes are related to more than one disease, and the pharmacology of drug-disease interactions reveals intricate connections between heterogeneous classes of therapies ( Systems Pharmacology, Drug Disease Interactions).