Demystifying Pharmacogenomics Testing, Clinical Applications, and
Implementation

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Presented By:

Ruben Bonilla Guerrero, MD, FACMG, FAACC
Sanjeda R. Chumki, PharmD, RPh

Pharmacogenomics is the study of how genes affect a person’s response to drugs. Pharmacogenomics testing combines pharmacology (the science of drugs) and genomics (the study of genes and their functions) to help to establish an effective, safe, and cost-effective therapeutic plan basedon a person’s genetic makeup.

Currently, the historical empirical success/fail therapeutic method still prevails as most pharmacological clinical trial studies are still conducted addressing one medication at the time documenting the improvement or not of the target condition and the presence or not of negative side effects (called adverse drug reactions). Therefore, producing results that suggest a “one size fits all,” approach.

Lack of therapeutic efficacy in combination with adverse drug reactions are a significant cause of hospitalizations and deaths in the United States and around the world. This combination is also responsible for an increased in all aspects of healthcare as by definition healthcare is based on the prevention, diagnosis, and successful treatment of patient’s conditions; and its failure prolongs healthcare needs.

Like other aspects of laboratory medicine, there is a technical aspect to pharmacogenomics, and it is essential to acknowledge the different forms of molecular variations present in genes associated with drug response and to identify the technologies that can accurately detect them.

Pharmacogenomics is not a new area of laboratory medicine, and it has been around since the discovery of the cytochrome P450 superfamily of metabolic enzymes in 1955. Today, the genomics study of drug response expands beyond drug metabolism (pharmacokinetics), to include drug targets (pharmacodynamics), immune-mediated drug reactions, and more. However, the application and implementation of pharmacogenomics into everyday clinical practice are relatively new.

The clinical applications of pharmacogenetics are rapidly growing at the rate as new medications are produce and current ones relate to genes involved in drug response. Some of the clinical application areas include pain management, anesthesia, cardiovascular disorders, oncology, psychotropics, infectious diseases, gastrointestinal medications, neurology to mention some of them, and it expands to all ages of life. However, there is confusion regarding its implementation, patient selection, and most important about what to do with results.

Lack of pharmacogenomics technical and clinical standardization fuels uncertainty and slows or impairs confident implementation. There are several independent organizations around the world including regulatory agencies such as the US Federal and Food and Drug Administration (FDA), best practice professional organizations such as the Clinical Pharmacogenetics Implementation Consortium (PCIC) in the US, the Dutch Pharmacogenetics Working Group (DPWG) in Europe, as well as compiling web-based organizations like PharmGKB attempting to bring organization and direction to the clinical application of pharmacogenomics.

In this presentation, we will clarify the technical and clinical aspects of pharmacogenomics, as well as provide a practical guide to its implementation, patient selection while taking in consideration all nongenetic patient’s factors that contribute to drug response.

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