Author(s): Wei Zhang 1 , Thomas YK Chan 2 , Lan Fan 1 , Ying Guo 1 , Hong-Hao Zhou [**] 3
personalized medicine; pharmacogenetics; pharmacogenomics; translational research
With rapid development in biomedical fields, particularly genomics, proteomics and bioinformatics, translational medicine has become a hot topic in biomedical research. Translational medicine is a practice that turns the outcome of corresponding biological research into drugs or medical devices that can be used in the treatment of patients, and is based on interventional epidemiology. The essence of translational medicine is to seek for molecular targets for the prediction and early intervention of diseases, design of personalized therapy based on the role of genetic and genomic factors in the individual response to drugs, and new drug development. This revolution in genomic and personalized medicine contributes to the foundations of predictive, preventive, personalized and participatory (P4) medicine  . Here, we summarize the international status of translational research in pharmacogenetics and pharmacogenomics towards personalized medicine and new drug development.
Adverse drug reactions, public health & pharmacogenetics
Adverse drug reactions (ADRs) constitute a substantial burden for the community. In Europe, ADRs account for 5.1% of hospital admissions and the incidence increases with age up to 9.8%  . In elderly patients, 40% of the ADRs causing hospitalization are judged to be avoidable  . A large meta-analysis of hospitalized patients in the USA estimates that ADRs account for 4.6% of all fatalities  . The potential role of pharmacogenetics and adverse drug events were systematically described by Phillips et al  . Among 27 drugs frequently cited in ADR studies, 59% are metabolized by at least one enzyme with a variant allele known to cause poor metabolism  .
Interindividual variations in drug responses or ADRs can be due to genetic differences in the activities of enzymes that are involved in the uptake, binding and metabolism of drugs. Pharmacogenetics should facilitate safe, effective use of drugs and substantially reduce serious ADRs.
Many drugs were withdrawn from the market because of an unacceptable frequency of serious ADRs occurring in a minority of patients. The withdrawal occurs to protect the minority who developed the ADR, at the expense of the majority who should benefit from the drug without developing any ADRs. Thus, pharmacogenetic testing provides the opportunity of 'rescuing'â drugs that are beneficial to the majority of patients while avoiding their use in those who will have adverse reactions.
According to a study in 2000, 35% of investigational new drugs were not marketed because of safety problems, and 4% of marketed drugs in the past 20 years have been withdrawn from the market because of safety issues, while on average a marketed drug costs approximately US$1-1.2 billion and takes 10 years to develop  .
Aim of pharmacogenetics & pharmacogenomics
Pharmacogenetics and pharmacogenomics aim to study the effects of gene mutations related to drug metabolism, transport and receptors on the drug'âs efficacy and toxicity, thus identifying genetic markers that help predict drug-related beneficial and harmful effects. In 2004, the Association of Human Single Nucleotide Mutations completed identifying...