Pharmacogenomics

Pharmacogenomics applies the large-scale systemic approaches of genomics to drug discovery and development. It also involves the study of the mechanisms by which drugs change the expression of genes, including drug-metabolizing enzymes, a phenomenon known as induction. Various technologies enable the analysis of these complex multifactorial situations to obtain individual genotypic

Fig. 18.1 Role of pharmacogenetic biomarkers in personalized medicine (© Jain PharmaBiotech)

and gene expression information. These same tools are applicable to study the diversity of drug effects in different populations. Pharmacogenomics promises to enable the development of safer and more effective drugs by helping to design clinical trials such that non-responders would be eliminated from the patient population and take the guesswork out of prescribing medications. It will also ensure that the right drug is given to the right person from the start. In clinical practice, doctors could test patients for specific SNPs known to be associated with nontherapeutic drug effects before prescribing in order to determine which drug regimen best fits their genetic makeup. Pharmacogenomic studies are rapidly elucidating the inherited nature of these differences in drug disposition and effects, thereby enhancing drug discovery and providing a stronger scientific basis for optimizing drug therapy on the basis of each patient’s genetic constitution. Pharmacogenomics can now be redefined as the study and application of DNA-, and RNA-based biomarkers to predict how an individual’s genetic inheritance affects the body’s response to a drug. Pharmacogenomic biomarkers should be able to predict drug efficacy in clinical trials. Discovery and validation of pharma- cogenomics biomarkers can lead to the development of pharmacogenomic tests that can be used to personalize therapy.