Pharmacogenomics is the field of understanding how an individual’s genetic inheritance affects the body’s response to drugs. Pharmacogenomics extends the study of pharmacology to modern genetics and allows an examination of the genetic basis for variation in individual response to treatments.

Knowing the full genetic complement of the human genome, the development and testing of drugs can be assessed at a molecular level and can take into account individual genetic differences. Much of pharmacogenomics depends upon people agreeing to have their genetic code tested.

Why is pharmacogenomics research important?

Pharmacogenomics holds the promise that drugs might one day be tailor-made for individuals and adapted to each person's own genetic makeup.
Potential benefits of pharmacogenomics include: new biomarkers, better drug design, and facilitation of personalized medicine—the ability to offer the appropriate treatment to the right person. Current methods of basing dosages on weight and age will be replaced with dosages based on a person's genetics --how well the body processes the medicine and the time it takes to metabolize it.

This will maximize the therapy's value and decrease the likelihood of overdose. Moreover, advances knowledge of particular disease susceptibility will allow careful monitoring, and treatments can be introduced at the most appropriate stage to maximize their therapy.

It is anticipated that more applications will appear at a rapidly increasing rate in the next three to five years, but that the full promise of pharmacogenomic applications will not be fully realised for at least another ten to fifteen years.

Limitations of pharmacogenomics research

Problems with pharmacogenomics at present are the vast varieties of protein sequences, called single nucleotide polymorphisms (SNPs).
A single variant can change the pharmaceutical needs of the individual, and it can take a long time to spot one variant. At this time, medical researchers don’t necessarily know which genes respond to certain drugs, or how they react to them.

Another issue pharmacogenomics encounters is the current idea of mass production of single drugs by pharmaceutical companies. This mindset of “one size fits all” medication would have to be rejected by pharmaceutical companies in favour of creating much smaller batches of medication or vaccines, precisely tailored for certain genetic codes. Further, a significant learning curve would exist for doctors in prescribing medications based on pharmacogenomics. They would need to learn how to analyse each patient’s gene variations in order to know what to prescribe, and in what dosage.

What the future holds for pharmacogenomics research

In the near future, the adoption and cost effectiveness of the new treatment regimes, rather than major developments in genomic technology itself, will most likely set the pace of progress in pharmacogenomics. However, in the fast-moving field of genomics, technological advances will continue to play an important role.

Whereas five years ago only a handful of companies were using genomic technologies in their clinical testing, currently an estimated 20% of U.S. clinical trials use some sort of genomic approach. A growing number of pharmaceutical companies are also collecting and banking blood samples during clinical trials—not for current genomic testing, but for potential future applications. In addition, many clinical trials are now being designed with genomic testing in mind.

Genomic products that have applications in the practice of medicine have begun to appear more regularly in clinical settings and are finally receiving regulatory approval. Recent milestones include: the first microarray approved for treatment decisions by the US Food and Drug Administration (FDA); the first drug to undergo an explicit genetic-risk review by the US FDA; and the first pharmacogenetic test approved as a companion diagnostic to a specific drug therapy.

The field of pharmacogenomics holds great promise. For those who cannot take certain medications because of adverse reactions, hope exists that medications might some day address each individual’s specific health needs. However, more research is needed to truly put pharmacogenomics into everyday practice.

Reproduced with the kind permission of Cancer Council New South Wales.