PGx: A promising field, not yet ready for widespread use

The following article was originally posted on the Mercer US Health News blog. You can find this article along with more health news content here.

By Dulari Parikh, Clinical Pharmacist/Principal, Mary Kay O'Neill, Partner, Clinical Services Consultant and Kathleen Wubbenhorst, PharmD, Principal, MercerRx

Pharmacogenomic (PGx) testing is a type of genetic testing that aims to personalize medication by analyzing an individual's genetic makeup. As pharmacogenomics vendors enter the market and Pharmacy Benefit Managers launch PGx programs, employer health plan sponsors are asking how this type of testing should be addressed in benefits offerings.

There are a limited number of medications that require PGx testing to ensure safety and adequate treatment response. Testing is currently required by some drug manufacturers and by the FDA for disease states such as oncology, cystic fibrosis, HIV and hemophilia; in such cases, testing would be integrated into the drug approval process. PGx testing may prevent unwanted side effects and unnecessary costs for therapies that are ineffective.

For most drugs, scientific evidence to support PGx testing is currently lacking

Over the past few years, diagnostic companies and pharmacy vendors have begun promoting PGx testing for select medications to treat specific disease states, such as attention deficit disorder, pain and depression. Yet there are currently no accepted guidelines for PGx testing for these drug classes. While pharmacogenomics is a promising field that holds great potential for the future of medicine, Mercer is not yet recommending its widespread use due to the lack of standardization, cost, the demonstration of improved outcomes and the potential for treatment delays.

The lack of standardization can make it difficult for healthcare providers to interpret the results and make informed decisions on treatment plans. Tests may not take into consideration factors such as race, gender, environment or lifestyle. As a result, prescribers have been slow to recommend testing to their patients. Additionally, members may refuse to take a test in fear of their genetic information being shared both with their employer and more broadly to external companies.

Costs related to PGx testing are not typically billed to the members. Plan sponsors pick up the costs which may run approximately $400 per test. Members may require more than one test depending on the number of conditions being tested.

In addition, some new direct-to-consumer vendors are utilizing at-home PGx kits that rely on testing via a cheek swab. A patient collects a DNA sample by swabbing the inside of the cheek then sends the sample to the associated laboratory. Results are typically available within a few days. The potential downside to patients’ pursuing testing that has not been recommended by their physician is a delay in treatment, if treatment is necessary, and stress for the patient. PBMs and medical vendors do not require utilization management—for example, prior authorizations—that include genetic tests unless there is specific labeling from the manufacturer or the FDA. Results of PGx tests may show preference for medications that are not covered on the PBM’s formulary. This may lead to members’ frustration and further delay of treatment if additional approvals are needed from the PBM. 

An evolving field

It’s important to keep in mind that in the cases where the data is clear, these tests are already required prior to a medication being prescribed – and that our concerns are with testing that does not fall into this category. There is still much to be learned about the relationship between genetics and drug response. While some genetic variations have been linked to specific drug responses, many others have not. Current data does not show better clinical outcomes for most drug types. Of course, your medical plan and/or PBM should be closely monitoring and updating their processes as clinical evidence evolves.

As the field evolves, we will continue to monitor its progress and provide updates on its potential application in healthcare and benefit offerings.