Clinical pharmacogenetics and future prospects in drug therapy

The human genome project has a large impact on various drug-related fields including drug discovery and clinical medication. Although clinical pharmacogenetics introduced the importance of studying genetic factors determining inter-individual variation on drug response for establishing a personalized medicine, which will be achieved in this century, recent strategies for exploring the genetic factors drastically differ from those of classical pharmacogenetics. The usefulness of an application of findings obtained from basic researches to a medication is uncertain at present because of limited in vivo evidence on the significance of genetic polymorphism to ensure an efficacy or to avoid adverse reactions of the drugs. In this review, a brief history of pharmacogenetics and the current status of the research are summarized. A number of problems that make it difficult to do clinical trials to clarify the significance of genetic polymorphism are discussed. Finally, it is expected in the near future that information on genetic variation with in silico technologies may predict the response toward drugs in each patient with various physiological and therapeutic conditions.