The road ahead for pharmacogenomic testing

Pharmacogenomic (PGx) testing may have the potential to revolutionize prescription drug use in Canada by tailoring treatment to individual patients — and save public and private payers billions in healthcare spending — but significant barriers still stand in its way.

PGx testing assesses how an individual metabolizes a drug based on variations in their genes — and thus has the potential to improve health outcomes by helping patients obtain the most compatible medication on the first try and thus reduce side effects. Plan sponsors, in turn, can realize reductions on drug costs, short- and long-term disability costs, absenteeism and presenteeism. 

PGx tests (which range in price from $300 to $1,500) are currently not covered by public health plans in Canada, although they can be purchased by consumers online, at community pharmacies and through workplace benefits programs. Most insurers now offer the testing to plan sponsors through healthcare spending accounts as a group insurance option or at a preferred pricing rate.

Despite the effectiveness of PGx testing (an ongoing pilot project by Manulife has found 80 per cent of members changed their medications as a result of the testing and 86 per cent reported an improvement in their mental health) uptake has been slow due to a number of factors. The tests are new, unregulated, unstandardized and, perhaps most significantly, employees may have concerns about the privacy of the test results.

Canada’s Genetic Non-Discrimination Act, passed in 2017, prohibits any person or organization from requiring an individual to undergo a genetic test or disclose its results. The Act defines genetic testing as an analysis of genetics “for purposes such as the prediction of disease or vertical transmission risks, or monitoring, diagnosis or prognosis.” While PGx testing focuses on drug compatibility rather than disease detection, it is not exempt from the legislation.

“Any genetic testing, including PGx, falls under this Act, even though no information from PGx tests is shared with insurers or plan sponsors,” says Matthew Gaudry, Director of Product Support and Management for Canada Life.

Perhaps more to the point, the Act means that insurers and plan sponsors cannot require or automatically include PGx testing as part of prescription drug coverage. That means uptake by plan members and plan sponsors alike will take time.

“While thousands of members have already benefited from these tests, there remains an opportunity for thousands more to benefit,” says Gaudry. Ongoing communication with employees is key to reassure them that their employer cannot access the test results. “There also needs to be better communication to plan sponsors who may be hesitant about covering the tests,” he says.

Canada Life offers a referral program for members to obtain a lower price on voluntary PGx testing ($100 off the regular test price of $599). In some cases, for employees on disability for example, the testing is made available at no cost. “This would be in the case where a case manager feels this intervention is appropriate. The testing can reduce the time it takes to get stabilized by months, if not years,” says Gaudry.

PGx testing has proven to be particularly effective for medications to treat mental health conditions. Studies have shown that genetic factors are responsible for up to 42 per cent of the variation in how people respond to antidepressants. With dozens of antidepressants available, patients often have to try several medications over a period of months before achieving the optimal treatment. Since one in 10 Canadians will experience major depression in their lives, PGx testing has the potential to make a huge difference in health outcomes while saving billions in healthcare costs.

A study published in November 2023 in the Canadian Medical Association Journal found the use of PGx testing in patients with depression could save B.C.’s public health system alone almost $1 billion over 20 years.

“These tests have been around for several years, but they are still relatively new,” notes Gaudry. “As long as they continue to provide value, we will continue to make them available to our members and in time we expect to gain an even better understanding of how effective they are in terms of health outcomes.”

Governments may also help raise public awareness and allay concerns. B.C. appears to be the first to do so: in June 2023, its office of Precision Medicine and Genetic Services released guidance for patients and providers on incorporating PGx testing in healthcare decisions. In its introduction, the guidance states it “provides a foundation for the development of PGx standards of practice in B.C.”

In summary, despite growing and consistent evidence of the clinical and economic benefits of PGx testing, privacy rules and lack of industry regulation require the careful navigation of uptake. Standards of practice and clinical guidelines will certainly help pave the way and allay the concerns of patients and clinicians. However, these take time. Until then, insurers, benefits advisors and plan sponsors can confidently communicate their benefits and facilitate access through private health benefits plans.