Medical Liability in Pharmacogenetics - Risk vs. Benefit

Medical Liability in Pharmacogenetics – Risk vs. Benefit

Ruslan Dorfman, PhD, MBA Precision Medicine in Practice

The risk of side effects and adverse reactions is a constant threat when physicians prescribe medication. Pharmacogenetics (PGx) tries to mitigate that risk. Traditional prescribing takes age, weight, sex, and biochemical test results when available into account. Pharmacogenetics uses genetic testing to assess variations in drug metabolizing genes to understand how individuals respond differently to common medications. This information enables physicians to determine an optimal medication and dose. The goal is simple: to reduce adverse drug reactions and improve treatment outcomes by predicting drug response based on a person’s genetic profile. This is becoming standard of care, so why the controversy? It seems obvious that additional information to examine prior to prescribing will result in less physician liability as an extra step is being taken to increase efficacy and safety and reduce the chance of adverse reactions and side effects.

A healthy dose of skepticism surrounding new medical technologies is warranted as new technologies pose new risks. The difference between pharmacogenetics and other innovations is that PGx testing reduces risk rather than creates risk. The additional information generated from highly sensitive PGx tests can only help and not hinder the decision of which medication and dose to prescribe. PGx testing is another tool in a physician’s toolbox to find the best-suited medication for each individual patient.

For many prescription drugs significant portions of the population are poor or rapid metabolizers and require non-standard doses to reach therapeutic levels or avoid toxicity. PGx avoids the tedious and potentially harmful trial and error period to find the right dose. PGx-guided prescribing, ideally conducted before treatment, can alleviate debilitating side effects and reduce non-compliance. The correlation between a patient’s inherited drug metabolism and drug response is well known for many medications and 137 drug-labels contain PGx-related information¹. Regulatory agencies including the FDA, Health Canada and the European Medicinal Agency mandate warnings on certain drug labels to undergo PGx testing to check if doses should be altered accordingly. Black-box warnings are known for clopidogrel, a common heart disease medication to reduce risk of stroke, and warfarin, an anticoagulant. Since genotype specific dosing is increasingly appearing on drug labels, it is critical that physicians understand how to utilize results of PGx testing to best treat patients and reduce adverse outcomes.

Fear of liability on behalf of physicians must be debunked. Consider a patient who chooses to take a PGx test and brings the report to their physician. The physician may be hesitant to act on recommendations from the report out of fear of being legally liable. Let’s explore why it is in a physician’s best interest to embrace information from a PGx test report.

Scenario A – ‘normal’ metabolizer

A patient finds out they are a normal metabolizer for the drug they are prescribed. They have assurance that they can take a standard dose and avoid an adverse reaction. The patient may be frustrated as the test was expensive and did not alert them of any new information. While this information, albeit non-exciting, is valuable, the physician carries on as they would had the test not been performed. The patient may be frustrated with the expense of the test but this will be directed at the PGx company not the physician. The physician now has the reassurance that their prescription will result in a good outcome for the patient.

Scenario B – ‘poor’ or ‘rapid’ metabolizer

A patient finds out they are a poor metabolizer for a certain drug and their PGx report recommends an alternative medication.

If the physician prescribes the recommended alternate medication and the patient has a good response, both physician and patient will be thankful for the PGx-guided prescribing.

If the physician ignores the recommendation and carries on with treatment, the patient can either experience adverse effects or respond normally. If the patient responds normally, they will doubt the validity of the PGx test and applaud the physician for their guidance. If the patient experiences adverse effects, then the physician could be liable for failure to adhere to PGx recommendations. Note: this is the only scenario in which the physician can be liable, if they fail to consider information that could notify them of potential adverse reactions.

In the genomic medicine age, physicians face growing risks of legal claims for genetic malpractice. A woman who developed Stevens Johnson Syndrome after being prescribed carbamazepine sued her healthcare provider for not first recommending genetic testing as instructed by the FDA-approved label of this drug for patients of Asian ancestry².

In their article Personalized Medicine and Medical Malpractice, Gary Marchant and Rachel Lindor discuss the rapidly changing field of personalized medicine and the liability risk it poses for physicians. They emphasize the lack of preparedness in the provider community and how this gap in knowledge poses unique liability challenges³. Physicians may be hesitant to incorporate PGx testing into their repertoire because they are not comfortable with interpreting PGx reports and adopting their recommendations. The increased utility of PGx testing mandates more training in this area to reduce the chance of diagnostic errors that could occur as a result of misinterpreting test results³. Marchant and Lindor explain how a more objective approach of reasonableness is being used to assess malpractice claims³. This is a shift from previously accepted defense arguments based on practicing the “local custom standard”³. This poses a new risk to physicians who are uninformed on how to incorporate genetic testing into their practices. Currently, physicians can be liable for failure to consider genetic testing when such tests would be mandated by a reasonable opinion i.e. if the drug contains a black-box warning.

Liability only becomes an issue when physicians ignore PGx testing, not when they take PGx recommendations into consideration. As the number of patients inquiring about PGx testing increases, the risk of liability increases so long as a gap exists between physician knowledge of pharmacogenetics and its proliferation. A barrier to integration of PGx into clinical practice is this gap in knowledge but ongoing learning opportunities for physicians have the potential to bridge this gap⁴. Pillcheck strives to reduce this gap by providing physicians with free resources to learn how PGx can help their patients. At Pillcheck we work with physicians to make personalized care more accessible and understandable. We encourage physicians to browse our website and educational materials and are happy to answer questions and provide more information upon request. Please see pillcheck.ca/providers/ for more information.

Author

Ruslan Dorfman, PhD, MBA

Founder and CSO Ruslan Dorfman is a trailblazer in personalized medicine, a molecular geneticist, and technology builder. Inspired by direct interactions with Cystic Fibrosis families from all over the world, Dr. Dorfman co-founded GeneYouIn to facilitate access to advanced genetics for the general public. He managed large-scale R&D programs at Sick Kids Hospital, Toronto. He advised Bridgepoint and Mount Sinai hospitals on the implementation of personalized medicine programs. Dr. Dorfman has published thirty peer-reviewed papers on the genetics of Cystic Fibrosis and Pain.

Medical Liability in Pharmacogenetics – Risk vs. Benefit

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