Martin Dawes speaking with a TreatGx participant.
A UBC project that uses patients’ genetic information to inform prescribing decisions by physicians has demonstrated its feasibility through a small pilot project, and is now offering its services directly to consumers.
In an article published this week in the CMAJ Open, the creators of TreatGx describe how their pilot project, involving five family practices and one pharmacy in metro Vancouver and on Vancouver Island, was used 236 times over a three-month period. The participating health professionals stated that the clinical decision support made it easy to use genetic information in deciding which drugs to prescribe and helped reduce inappropriate prescribing.
TreatGx uses a sampling of genetic data – culled from patients’ saliva samples – to try to prevent the use of drugs that would be ineffective or harmful due to a patient’s genotype. The pilot project focused on drugs used for 15 common conditions, including depression, hypertension, hyperlipidemia (high cholesterol) and diabetes.
A single mutation can spell the difference between a drug being useful, or being deadly. One mutation on a gene called CYP2C19 causes rapid metabolizing of two commonly used anti-depressants, diminishing the drugs’ effectiveness; another mutation on that same gene could have the opposite effect – slowing down metabolization, thus heightening the risk of side effects. Another mutation causes codeine to be rapidly converted to morphine, posing a danger to babies drinking breast milk from women taking this common over-the-counter drug.
More than 150 medications approved by the U.S. Food and Drug Administration now carry such pharmacogenomic warnings. But without knowing a patient’s genetic make-up, a doctor cannot act upon them.
TreatGx uses specially-designed software that considers the usual details about a patient: age, weight, blood pressure, allergies, other medical conditions, other drugs they might be taking. It also includes the latest reliable evidence about the safety and effectiveness of the more than 250 drugs.
Layered on top of those inputs is genetic data about the patient in question – specifically, whether he or she has any of the 60 variations, spread across seven genes, that might render a drug ineffective or even harmful.
Rarely is pharmacogenetic data obtained from patients who don’t have a life-threatening disease, predominantly cancer. TreatGx is one of the first attempts at providing that information to primary care physicians and pharmacists, in a clinically useful manner, for more common illnesses.
“This is a made-in-B.C. software system that allows the physician and patient to select tailored drug options for multiple conditions,” said Martin Dawes, Professor and Head of UBC’s Department of Family Practice, who conceived and designed TreatGx, working with colleagues from UBC’s Personalized Medicine Initiative, a not-for-profit UBC spinoff.
The pilot showed the feasibility of obtaining usable saliva samples in primary care settings, and that almost all of the 189 participating patients had at least one actionable genetic variant that influenced which drug was prescribed. The trial also showed that such results could be readily incorporated into a medical decision support system in a primary care setting. The conditions for which TreatGx was most frequently used were hyperlipidemia and hypertension.
The development of the system and the pilot project were supported by Genome BC, the Michael Smith Foundation for Health Research, TELUS Health, Roche Canada, AstraZeneca, GSK, Janssen, Merck, Pfizer and Innovative Medicines.
TreatGx, the medical decision support system, will now be marketed along with myPGx, a cheek swab test kit, through a UBC spin-off company, GenXys. Consumers would take a swab from inside their cheek, and send it to GenXys through the mail for analysis and a report that can be shared with their physician and pharmacist. The analysis has been expanded to cover drugs used for 26 conditions.
“There are over 200,000 severe adverse drug events annually in Canada, costing upwards of $14 billion, which places a significant burden on the Canadian healthcare system,” explains Catalina Lopez-Correa, Chief Scientific Officer and VP, Sector Development at Genome BC. “Even if physicians have the pharmacogenetic information, incorporating it into their system is a significant challenge. We are proud to support research that is helping doctors access and streamline genetic information to further enhance patient outcomes.”