A case study to highlight the potential benefits of pharmacogenomic testing to proactively seek personalized treatment.
Case example:
Jane is a 62-year-old female with a past medical history significant for hypertension and dyslipidemia. The patient is active and enjoys daily walks with her husband. These conditions are currently well controlled by the combination of her active lifestyle and medication therapy.
Current Medications
- Losartan 50 mg daily
- Atorvastatin 40 mg daily
Background
Jane has been on this high-intensity dosage of atorvastatin for two years to manage her dyslipidemia. She has experienced mild to moderate bouts of muscle pain since the statin initiation but was told this is an important medication. Jane was told myalgia is a common side effect and she felt she had to live with it.
Jane recently received an opportunity to receive pharmacogenomic testing through her employer’s new benefits package. Jane took this opportunity as she wanted to learn more about her own genetics and how they might relate to her current and future medications. She discussed taking this test with her primary care provider (PCP), and her PCP, having heard about PGx’s potential benefits, agreed to sign off on the testing.
At Jane’s follow-up visit, PGx results are available for her PCP to view. There is information regarding a gene-drug interaction with atorvastatin, but not losartan.
Results
| Gene/Genotype | Phenotype | Implications |
| SLCO1B1 *1/*15 | Decreased Function | Increased atorvastatin exposure as compared to normal function which may translate to increased myopathy risk. |
The results reveal that Jane’s genotype at SLCO1B1 is *1/*15. This genotype is associated with a phenotype of reduced function and increased risk of statin-induced myopathy. Reduced SLCO1B1 function can lead to an increased plasma concentration of statins, which in turn increases the risk of statin-related side effects, including myopathy.
Considerations
Upon receiving the test results, Jane and her PCP discussed the significance of the SLCO1B1 genotype. During the discussion, Jane mentioned her muscle pain, prompting her PCP to connect it with the test results. Her PCP investigates the available guidelines and literature and finds the Clinical Pharmacogenetics Implementation Consortium (CPIC) guidelines for SLCO1B1 and statin therapy. These guidelines recommend a switch to rosuvastatin 20 mg which would allow for the maintenance of high-intensity statin therapy with consideration of lower risk for statin-related myopathy. After considering Jane’s other clinical factors and concluding this medication change was safe, her PCP makes the switch to the rosuvastatin 20 mg.
Conclusion
Through the PGx testing, a gene-drug interaction was discovered. As a result, they were able to make an informed decision to switch her medication, leading to improvements in her symptoms of a common side effect from statins. Furthermore, Jane’s PGx results will continue to provide valuable insights for future medication decisions. This case highlights how pharmacogenomics can facilitate more tailored and effective treatment plans, improving patient outcomes and safety.
Victor Tam, PharmD is a PGx certified clinical pharmacist and is currently a Senior Medical Science Liaison at OneOme LLC, a med tech company located in Minneapolis, MN. OneOme offers additional information and PGx education which can be found at OneOme.com/education.
