Personalized Medicine, Part 1: Theranostics

HISTORY AND LANDSCAPE Over the past six decades, much evidence has emerged indicating that a substantial portion of variability in drug response is genetically determined, with age, nutrition, health status, environmental exposure, epigenetic factors, and concurrent therapy playing important contributory roles. To achieve individual drug therapy with a reasonably predictive outcome, one must further account for different patterns of drug response among geographically and ethnically distinct populations. These observations of highly variable drug response, which began in the early 1950s, led to the birth of a new scientific discipline arising from the confluence of genetics, biochemistry, and pharmacology known as pharmacogenetics. Advances in molecular medicine have spawned the newer field of pharmacogenomics, which seeks to understand all of the molecular underpinnings of drug response. Commercialization of this research application is now known as personalized medicine (PM). Demonstrated success is emerging for several conditions and treatments, but whether PM will achieve widespread benefits for all remains as yet unrealized. For the average patient, the benefits have not yet been realized, but ultimately PM will affect the entire landscape of our health care system. Since the mapping of the human genome in 2003, the pace of discovery, product development, and clinical adoption of what we know as PM has accelerated. PM may be considered an extension of traditional approaches to understanding and treating disease but with greater precision. A profile of a patient’s gene variations can guide the selection of drugs or treatment protocols that minimize harmful side effects or ensure more successful outcomes. PM can also indicate an individual’s susceptibility to certain diseases before they become manifest, allowing physicians and patients to design a plan for monitoring and prevention. Physicians can now go beyond the one-size-fits-all model of prescribing to make more effective clinical decisions for each patient. PM offers a structural model for efficient health care; it is preventive, coordinated, and proven. PM works best with a network of electronic health records that link clinical and molecular information to make it easier to help patients and their physicians make appropriate treatment decisions. PM is participatory, engaging patients in lifestyle choices and active health maintenance to compensate for genetic susceptibilities. Substantial progress has been made toward implementing PM. When all of the pieces of infrastructure fall into place; when we begin to classify and treat diseases not only by their most obvious signs and symptoms but also by their molecular profiles; when physicians combine their knowledge and Dr. Vogenberg, a P&T editorial board member, is Principal at the Institute for Integrated Healthcare in Sharon, Mass.; Executive Director of the Biologic Finance and Access Council at Jefferson School of Population Health in Philadelphia, Pa.; and Adjunct Instructor of Pharmacy Administration and Health Economics at the University of Rhode Island in Kingston. Dr. Barash is Founder and Principal of Genetics, Ethics & Policy Consulting, Inc., in Boston, Mass. Mr. Pursel is employed at Teva Neuroscience in Kansas City, Mo. Personalized Medicine Part 1: Evolution and Development into Theranostics