Introduction to Pharmacogenetics

Concept and Definition of Technology

Concept: Pharmacogenetics can be defined as the study of hereditary factors contributing to variability in human drug response. Essentially, this branch of genetics studies the how an individual reacts to drugs and other pharmacological products to further understand genetic differences between different humans. This in turn leads to personalized medicine for various genetic disorders, or to help researchers understand how different drugs and pharmaceuticals affect different genetic or chromosome-linked disorders. Another strong concept in this field would be that the driving force for such studies was the suggestion, made over half a century ago, that many abnormal responses to drugs might be due to genetically determined variation.

Based on DNA: With the unravelling of the structure of DNA³, and subsequent development of molecular biology, it soon became possible to study associations between genotype (DNA mutations) and phenotype (observable or measurable traits including clinical presentation). As the scale of the investigations became more ambitious to find other genetic patterns and the enabling technologies more sophisticated, the term ‘pharmacogenomics’ was coined to allow association studies on a genome-wide basis. In the clinical arena, both terms can be used interchangeably.

Basic Science: The study of pharmacogenetics promises to hold a lot of potential. Pharmacists have had to deal with the various ailments of people for a long time, while looking to understand the concept of their problems. When they would try to understand why these genetic disorders occur and which drugs or compounds would remedy the situation, they would inadvertently dabble in this field. As years have gone past, we have learned to associate certain drugs and the implications of their affects and our understanding of genetic altering grew. With this approach we should theoretically be able to predict response to an increasing array of drugs and thereby personalise therapy with appropriate pharmacogenetic testing.

Economic Issues

Economic Issues: Personalized medicine and drugs promise to improve healthcare by increasing drug efficacy and minimizing side effects. There may also be substantial savings attained by eliminating costs associated with failed treatment. One common method used to determine the economic effectiveness and impacts of this field are health claims on data for analyzing the potential value of pharmacogenomic testing in clinical practice. For example, in a set study, a model of alternate clinical strategies was evaluated using asthma patients' data from a retrospective health claims database to determine a potential cost offset. The likely cost impact of using a hypothetical pharmacogenomic test to determine a preferred initial therapy was estimated. The annualized per patient costs distributions was compared under two clinical strategies: testing all patients for a nonresponse genotype prior to treating and testing none.

RESULTS:

In the Test All strategy, more patients fall into lower cost ranges of the distribution. In the base case (15% phenotype prevalence, 200 US dollars test, 74% overall first-line treatment efficacy and 60% second-line therapy efficacy) the cost savings per patient for a typical run of the testing strategy simulation ranged from 200 US dollars to 767 US dollars (5th and 95th percentile). Genetic variant prevalence, test cost and the cost of choosing the wrong treatment are key parameters in the economic viability of pharmacogenomics in clinical practice.

CONCLUSIONS:

A general tool for predicting the impact of pharmacogenomic-based diagnostic tests on healthcare costs in asthma patients suggests that upfront testing costs are likely offset by avoided nonresponse costs. It is suggested that similar analyses for decision making could be undertaken using claims data in which a population can be stratified by response to a drug.

A helpful diagram, distinguishing the two terms

The difference between Pharmacogenetics and Pharmacogenomics

Political/Societal Issues

Political/Societal Issues: One societal issue that has the potential to happen would be that a major breakthrough in preventing/healing genetic disorders would occur. However, the treatment is likely to not be affordable for most of the human population. This would in turn lead to pharmaceutical companies securing a lot of power and money. The majority of the population however, would not be able to get the treatment that they would need. This also breaches ethical concerns.

Questions concerning justice are a legitimate ethical concern from the perspective of disadvantaged individuals. The cost of drug development raises questions of government, industry, and insurance company responsibilities to individuals whose pharmacogenetic responses are in a minority. It is often a question if the development of pharmacogenetics will benefit low and middle-income countries due to the cost of experimental procedures and the drugs themselves to be very expensive. These questions are of great importance, but it is of equal importance to address them to the right audience. In my view, it is wrong to ask the scientists or the pharmaceutical companies to answer these questions. It is not their task, and neither is it their task to be concerned about societal implications regarding scientifically-based definitions of genotypes and 'epigenotypes'. Individual scientists and company executives may feel a moral duty to contribute to a just world and to help those who have been disadvantaged owing to earlier injustice from the rich and powerful in particular. Sentiments like these are commendable but are entirely private concerns and nothing that can be imposed on these individuals by society.

Pharmacogenetic Testing Informational Video

It explains the whole notion of pharmacogenetics and its applications in the real world.

Environmental Issues:

Environmental Issues: No direct issues or environmental impacts come directly to mind, however there could be a question asked of the disposable system of the byproducts of biological experimentation. As with properly disposing unwanted chemical products at the end of an experiment in chemistry, live organisms that were experimented on would have to be killed and then disposed of. Now the question remains: where do we dispose of it? The remains of these animals and perhaps even humans are not always naturally able to decay properly, and killing them after the experiment is over breaches all kinds of ethical concerns. Therefore, disposing of biological material afterwards could pose some sort of an environmental issue.