The promise and challenge of personalized medicine: aging populations, complex diseases, and unmet medical need.

The concept of personalized medicine is not new. It is being discussed with increasing interest in the medical, scientific, and general media because of the availability of advanced scientific and computational technologies, and the promise of the potential to improve the targeting and delivery of novel medicines. It is also being seen as one approach that may have a beneficial impact on reducing health care budgets. But what are the challenges that need to be addressed in its implementation in the clinic? This article poses some provocative questions and suggests some things that need to be considered.