What is pharmacogenomics?
Pharmacogenomics is the technology that explores the effects of genetic information on drug responses. Genomics generally means all or most of our genetic material, where as we use the term genetics when we talk about single gene effects or a small number of genes.
Why is pharmacogenomics becoming so important?
Drugs are used in an enormous array of settings, from prevention to treatment, and it has long been noticed that people’s response to drugs varies. In 2010 the Therapeutic Goods Administration received 14,200 cases of severe adverse drug reaction. Reasons for this variability include environmental issues such as nutrition, drug interactions, when people take multiple drugs, and an individual’s genetic makeup. With the increasing technology occurring in genetics we now have the ability to obtain huge amounts of genetic information, our genome, relatively quickly and at lower cost.
How is it being used?
In the USA, the Federal Drug Administration, is developing tools for integrating genetic and other biomarker information into drug and device development and clinical decision-making. To date over 100 drugs have labels that include information about testing for specific genetic information prior to drug prescription. A link to this list of drugs is http://www.fda.gov/Drugs/ScienceResearch/ResearchAreas/Pharmacogenetics/ucm083378.htm
An international group of people has formed the Clinical Pharmacogenetics Implementation Consortium (CPIC) and have developed a number of guidelines for genetic testing and specific drugs. The list of which is provided at http://www.pharmgkb.org/page/cpicGeneDrugPairs
In Australia, two pharmacogenetic tests are covered by Medicare and their use is aimed at preventing adverse effects from specific drugs; HLA-B*5701 to guide HIV therapy abacavir, and TPMT gene testing to guide therapy with thiopurine drugs. The pharmaceutical benefits scheme that subsidises the cost of medicines in Australia, uses genetic test results to determine a person’s access to subsidised medicines. For example KRAS mutations for cetuximab (colon cancer), EGFR mutations for gefitinib (for lung cancer), and HER2 mutations for trastuzumab (breast cancer). For these situations there is strong evidence that the specific genetic site significantly impacts on the efficacy and safety of the drug. Over time there will be more evidence around DNA sites and drug interaction leading to more guidance on testing and drug prescription.