Some applications of pharmacogenomics and epigenetics in drug development and use in pursuit of personalized medicine.

Personalized medicine has become the most recent mantra of the pharmaceutical industry. While truly affordable bespoke drugs may never be totally achievable, pharmacogenomics and epigenetics will play significant roles in developing targeted therapy tailored to subpopulations of disease sufferers most likely to benefit. Personalized medicine is a very attractive concept, but an extremely difficult reality to achieve due to theoretical and practical considerations. Foremost among the theoretical reasons is our dearth of knowledge of individual physiology and metabolism, as well as the interactions of genetics and environment in the development of most diseases. Amongst the practical reasons, there is the cost of new drug development, considered to be about 800 million to one billion dollars (J Health Econ 22:151-185, DiMasi et al. 2003; Health Econ 19:130-141, Adams and Vu Brantner 2010) and the fact that many drugs now on the market do display reasonable efficacy in large segments of the population with acceptable side effects. Thus, the market for "personalized" drugs may not be large enough to support the costs of development. Another factor is the limitations put on healthcare by governments and insurance companies which promote the use of generics rather than the creation of new chemical entities. Finally, there are the social and ethical considerations of turning individual biology into noughts and ones with the possibility of such information becoming public and/or being used to constrain the way one lives or the care one receives (Nat Rev Drug Discov 1:300-308, Issa 2002). That said, to the degree that personalized medicine does become possible, pharmacogenomics and epigenetics will play significant roles in drug development and use.