What Is Pharmacogenomics?

It seems obvious that doctors and the pharmaceutical industry should always be striving for the right drug, for the right patient, at the right dose . And yet, today’s standard prescribing practice could better be described as finding the “the right drug, for as many people as possible.” The good news is that thanks to exciting fields of study like pharmacogenomics, the practice of medicine is moving past a one-size-fits all approach.

Pharmacogenomics and Personalized Medicine

Pharmacogenomics is the study of how an individual’s genes impact that person’s response to drugs . This field of precision medicine combines pharmacology (the science of drugs) and genomics (the study of genes and their functions) to choose the drugs and drug doses that are likely to work best for each individual person. More than 250 drug compounds, which are contained in thousands of brand name and generic medications, have label information, regulated by the U.S. Food and Drug Administration (FDA), regarding pharmacogenomic biomarkers — some measurable or identifiable segment of genetic information that can be used to direct the use of a drug.

Pharmacogenomics is one aspect of the field of personalized medicine, sometimes called individualized medicine or precision medicine , which aims to address each patient with treatments that are as customized as possible. These advances in medicine help patients by removing both the pain and costs of trial-and-error treatment.

Today, tests to incorporate pharmacogenomic information in a patient’s care regimen are ordered as routine for only a few health problems. Additional research has shown that these tests can lead to better ways of using drugs to manage heart disease , cancer, depression, and many other common diseases.

Examples of Pharmacogenomics in Action

The National Human Genome Research Institute highlights several examples of how pharmacogenomics research is being applied in real life :

• Citalopram (Celexa) – Researchers recently identified genetic variations that influence the response of depressed people to citalopram, which is one example of a serotonin re-uptake inhibitor (SSRI). Clinical trials are now underway to learn whether genetic tests that predict SSRI response can improve how these drugs are used.
• Warfarin – The GIFT Randomized Trial found that patients whose pharmacogenomic information was utilized to guide their dosing guidance experienced a 33 percent reduction in severe adverse events.
• Abacavir (Ziagen) – Before prescribing this antiviral drug for HIV treatment, doctors now routinely test patients for a genetic variant that makes them more likely to have a bad reaction to the drug.
• Trastuzumab (Herceptin) – Doctors understand that this therapy works only for women whose tumors have a particular genetic profile that leads to overproduction of a protein called HER2.
• Mercaptopurine (Purinethol) – The FDA recommends genetic testing before giving this chemotherapy drug to patients with acute lymphoblastic leukemia. Some people have a genetic variant that interferes with their ability to process the drug and can cause
• Irinotecan (Camptosar) – The FDA also advises doctors to test colon cancer patients for certain genetic variants before administering this drug as part of a combination chemotherapy regimen. Patients with one particular variant may experience severe diarrhea and increased infection risk and need to receive lower doses of the drug.

Advances in pharmacogenomics and personalized medicine point to an exciting future where the medical community can provide more customized and effective treatments for patients.

This post is part of our “Ask an Expert” blog series by Ken Majkowski, Pharm.D, the Chief Pharmacy Officer at FamilyWize. Ken brings more than 40 years of healthcare experience to the FamilyWize team, including 14 years of clinical pharmacy experience in retail, hospital, and home care. Read his full bio here .

Sources:

• U.S. National Library of Medicine, “Genetics Home Reference – What is pharmacogenomics?” February 6, 2018
• MayoClinic.org, “Personalized medicine and pharmacogenomics.” June 5, 2015
• MayoClinic YouTube Channel, “Pharmacogenomics: The Right Drug, for the Right Patient, at the Right Dose.” February 20, 2017
• National Human Genome Research Institute (NHGRI), “FAQ About Pharmacogenomics.”
• FDA.gov, “Table of Pharmacogenomic Biomarkers in Drug Labeling.”