Simple Drugs Do Not Cure Complex Diseases: The Need for Multi-Targeted Drugs

Abstract

Systems biology has shown that the multi-factorial nature of complex disease networks and their intrinsic robustness against perturbation makes the rational design of multi-targeted drugs essential. Simple drugs cannot cure complex diseases. In both cancer and rheumatoid arthritis, highly complex networks are affected and many different cell types are involved. In cancer, disturbance of signal transduction leads to the evasion of apoptosis and growth control, and the induction of angiogenesis and metastasis. The key signalling pathways in inflammation are similar to those involved in cancer. Multiple factors, such as kinases, are involved in activating signalling pathways downstream from the T-cell receptor. Though polypharmacology is often associated with side effects, multi-targeted drugs when rationally designed can have a larger therapeutic window than those hitting a single target if the therapeutic effects overlap but the detrimental effects do not.