The study reassures that patients and healthcare professionals can use pharmacogenetic tests

A person’s genetic makeup can affect the possibility that they may experience side effects from certain medications. Some labs now offer pharmacogenetic tests that let patients know if they carry genetic variants known to be associated with adverse drug effects. Such tests could help patients and their doctors choose safer and more effective treatments, but the U.S. Food & Drug Administration and other regulatory agencies have expressed concern that patients may make unproven and inappropriate decisions about their medications based on to their pharmacogenetic results.

A new article published on December 3 in JAMA Network Open could help alleviate some of these concerns. Researchers from the VA Boston Healthcare System, Brigham and Women’s Hospital, and Harvard Medical School conducted a randomized controlled trial of pharmacogenetic testing of cholesterol-lowering drugs called statins. Statins, such as atorvastatin and simvastatin, are used by millions of Americans to reduce the risk of heart attack and stroke.

However, in rare cases, patients could experience muscle damage from statins, which can sometimes be serious and life-threatening. Pharmacogenetic tests can identify if a patient carries a genetic variant in the SLCO1B1 gene that puts them at a higher risk for such statin-associated muscle injuries. While this test may help patients avoid the adverse effects of the drug, it could also have the unintended consequence of causing patients not to do enough to reduce their risk of cardiovascular disease.

This study reassures that patients and healthcare professionals can use pharmacogenetic tests to maximize their benefits while avoiding unintended harmful consequences. Our results do not support the idea that all patients should undergo pharmacogenetic tests before starting a statin, but they do provide rigorous and real evidence that the harms of such tests are minimal. “

Jason Vassy, ​​MD, MPH, corresponding author, clinical investigator, Brigham, general practitioner at the VA Boston Healthcare System and assistant professor, Harvard Medical School

Vassy and colleagues enrolled 400 patients at the VA Boston Healthcare System who were not currently prescribed a statin but who had risk factors for cardiovascular disease that could make them candidates for statin treatment now or in the near future. The researchers conducted a controlled study in which statin pharmacogenetic results were provided to a random half of the participants and their primary care providers at the start of the study, while the other half received the results after one year. After one year, the cholesterol levels in the group that received their pharmacogenetic results were no higher than those in the group that did not receive their results, and they were no less likely to receive medical treatment within the recommended guidelines. In some cases, doctors may have used the results to choose an alternative, but equally effective, drug for the patient. Overall, the study’s findings suggest that pharmacogenetic testing did not cause patients and their primary care providers to be less proactive in reducing their risk of cardiovascular disease.

The authors note that fewer participants than expected were prescribed statin therapy in general, potentially a reflection of patient reluctance and physician prescribing patterns. Less than 16% of physicians documented talking to their patients about their SLCO1B1 in the intervention arm of the study.

Vassy said the team’s findings should allay stakeholder concerns about the potential unintended consequences of pharmacogenetic findings, a conclusion he says will become increasingly relevant as more patients undergo genetic testing as part of their healthcare.

“Many health systems have launched pharmacogenetic testing programs,” Vassy said. Such a program exists at Brigham through its pharmacogenomics clinic. “Our study offers empirical evidence that clinical use of pharmacogenetic test results for SLCO1B1 does not worsen patient outcomes, which we hope will help inform the debate about the usefulness and unintended harm of this type of test.”