Personalized Medicine and the Future of Pharmacogenomics

By Rustin Crutchley, Pharmacotherapy Associate Professor


Pharmacogenomics, a budding field of personalized medicine, is the study of how genes influence an individual’s response to treatment with medications. Drug-related morbidity and mortality due to unoptimized medication therapy is estimated to cost the United States $528 billion annually. According to the Centers for Disease Control and Prevention, adverse drug events (ADEs) have been categorized as a leading cause of preventable death in the United States. Almost 500 therapeutic products recognized by the Food and Drug Administration (FDA) include pharmacogenomic information in their drug labeling. Most of us carry at least one actionable pharmacogenomic variant that impacts the way we metabolize medication. Approximately, 20% of prescribed medications in the United States carry a labeled pharmacogenomic recommendation based on these variants. Major therapeutic areas involving these medications include oncology, psychiatry, cardiology and pain. Pharmacogenomics can help to remove the trial-and-error approach by providing health care professionals with informative guidance from the very beginning of treatment to prevent toxicity and improve overall effectiveness of medication use. For this reason, the College of Pharmacy and Pharmaceutical Sciences is launching an 8-week Interprofessional Clinical Pharmacogenomics Certificate Program on March 8, 2022. This program will be offered to both pharmacists and physicians for 16 hours of continuing education (CME/ACPE).

Although the origin of pharmacogenomics is unclear, early signs of its relevance potentially date back to 510 BC, where certain individuals experienced fatal hemolytic anemia (destruction of red blood cells) when ingesting fava beans. This was later shown to be due to an inherited deficiency of glucose-6-phosphate dehydrogenase (G6PD), which is important for protecting red blood cells from oxidative stress. G6PD deficiency is more commonly observed in African and Mediterranean ancestry. According to recommendations from FDA drug labeling, individuals who have G6PD deficiency should not use certain medications. Some examples include rasburicase (drug used for patients who undergo chemotherapy) and antimalarial primaquine. For this reason, knowledge of an individual’s genes can provide a personalized approach to ensure that an individual receives right medication and right dose.

Together, the mapping of the human genome project completed in 2003 and advances in technology have accelerated pharmacogenomic discovery broadening its clinical utility in practice settings. Today, the costs of whole genome sequencing have decreased significantly to less than $1,000 per individual. Pharmacogenomic testing for an individual is usually ordered when a health care provider suspects intolerable side effects to a medication or if a medication is not working. This is known as reactive testing. Although payer coverage for pharmacogenomic testing is not universally accepted in the United States, it is improving. Billing and coverage of some single gene tests has been supported by current procedural terminology (CPT®) codes, a universal language for coding medical services and procedures to streamline reporting and increase accuracy and efficiency. However, multigene panels are considerably more cost-effective than single gene panels, with this former approach covered by some large commercial payers, specifically, for individuals who have failed treatment with medications such as antidepressants and antipsychotics.

Greater clinical uptake of pharmacogenomic testing and consumerism is anticipated to grow exponentially in the future. Professional pharmacy organizations such as American Society of Health System Pharmacists (ASHP) support efforts to incorporate pharmacogenomics into clinical practice. Therefore, education of health care professionals is critical to keep pace with the rapidly evolving field of pharmacogenomics. This education is necessary for meeting the current needs of patients and ensuring optimization of patient treatment outcomes and long-term cost savings. The Interprofessional Clinical Pharmacogenomics Certificate program is an interactive practice-based program designed to equip physicians and pharmacists with greater readiness, confidence, and advocacy for optimizing medication management using pharmacogenomic data. This program will provide participants with a broad knowledge of fundamental pharmacogenomic principles and enhance their overall capacity to apply this information across multiple therapeutic areas in various practice settings to improve the delivery of patient care.

To learn more and register for Washington State University’s new course on pharmacogenomics, visit our continuing education platform in collaboration with the WSU Elson S. Floyd College of Medicine.