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Pharmacogenetic testing another step toward more personalized health care

Rhigel “Jay” Tan knew there had to be a better way. Like many of his colleagues, the UNLV professor and psychiatric and mental health nurse practitioner had long been skeptical of the trial-and-error approach to prescribing medicine for mental health patients.

For years, he and others had been scratching their heads over why one drug would produce fantastic results for one patient and bring nothing more than painful side effects to another.

A few years ago, Tan turned to pharmacogenetic testing for answers. The field, which has been around for several decades, is evolving rapidly with the push for more personalized care.

Even the federal government has a stake in the matter, earmarking $215 million in the 2016 budget for its precision medicine research initiative, which involves more research into pharmacogenetic testing.

Pharmacogenetic tests evaluate a person’s genetic metabolic pathways, most of which are in the liver, to ascertain whether a drug will be beneficial to that person. After a few years and a few hundred patient tests, Tan can honestly say the approach is a game-changer.

“There are certain drugs that genes in certain individuals simply don’t know how to use,” he said. “This defies the concept of one drug feeds all. Instead, it supports the idea of the right drug in the right amount for the right patient.”

Medical professionals agree pharmacogenetics is indeed the wave of the future, not just for psychiatric medications, but for many other drugs as well — even though barriers still exist.

HOW IT WORKS

A cheek swab is all it takes to gain insight into a person’s genes and how they affect a drug’s efficacy. Tan uses a California lab to analyze his patient samples and can usually get results back within a couple of days. His tests cover nine gene types. Some include: CYP2D6, CYP2C19 and MTHFR, or methylenetetrahydrofolate reductase, which is crucial to the body effectively using folate. Folate can also factor into a person’s ability to produce the mood-enhancing neurotransmitter serotonin.

Anil Malhotra, professor of psychiatry and molecular medicine at the Hofstra Northwell School of Medicine in Hempstead, New York, has been a pharmacogenetic researcher since the 1990s. One of his areas of research involves the connection between anti-psychotic drugs and weight gain. His researchers have used pharmacogenetic tests to link how an anti-psychotic drug activates the body’s D2 dopamine receptor.

“We did find that the gene influenced the response to the medication. … The results are so far ubiquitous across all currently available anti-psychotic drugs,” he added. “If someone’s at high risk for weight gain we recommend trying another treatment strategy.”

BEYOND MENTAL HEALTH

Pharmacogenetic tests can also help with other drugs. The CYP2D6 gene, for example, plays a big role in how effective many pain and cardiac medications can be for an individual.

“Two-D-six dictates the ability to metabolize about one-quarter of medications including many pain, depression and cardiac medications,” said Kristine Ashcraft, CEO of Seattle-based Genelex, a testing company that has worked in pharmacogenetics since 2000. “These tests can help optimize safety and effectiveness. … The testing doesn’t expire either; it can help guide your medication decisions for the rest of your life.”

Dr. Romualdo Aragon, a Las Vegas family practice physician, recently worked with Texas-based DNA STAT. The company allowed him to use its test for his patients for free. All of the patients he tested, which numbered more than a thousand, were on two or more medications, the bulk of which were not psychiatric medications.

The popular heart medication, Clavix, which prevents blood clots, is an example, Aragon said. The drug cannot be activated without the CYP2C19 enzyme.

“Your patient may have a deficient enzyme for that drug. If it’s deficient then it will not be transformed into its active metabolite,” he said.

Aragon’s experience with the tests was positive. After he obtained the test results and discussed them with his patients, he would in most cases send a patient back to his or her specialists to adjust doses or change prescriptions. That was the case for cholesterol-lowering drugs, heart medications, blood-pressure stabilizers and even some psychiatric medications.

“We even looked at pain killers, even over-the-counter ones like Advil. It could cause adverse effects that could be detrimental,” he said. “This information is all very important, especially in my profession, where I deal with diabetic patients, some with heart conditions and a lot of elderly patients on a lot of different medications.”

AFFORDABILITY, THE FUTURE

Today, the Food and Drug Administration has a list of more than 160 medications it recommends or allows pharmacogenetic testing. But insurance coverage is a barrier. After the DNA STAT study, Aragon has rarely used the tests, citing high costs and a lack of insurance coverage for patients. Most comprehensive tests can range from $500 to $1,000.

Aragon said more clinical trials are needed before more insurance carriers consider covering the tests.

Tan has had some issues with insurers not covering them, but has found some carriers open to it.

Ashcraft said the out-of-pocket cost for a Genelex comprehensive test, which must be ordered by a physician, costs $695 if insurance does not cover it.

“If you’re having a problem with your medication — and you think of the staggering numbers of people who do — it’s probably worth it. … Most people have a variation in one or more cytochromes,” she said.

Malhotra is optimistic about the future of the tests as more business interests want to enter the field, too. The researcher also consults with Genomind, a Pennsylvania-based personalized genetics testing company.

“Ultimately, it will become the standard because the cost will come down,” he said. “It’s still in the early phase for many of these products, but I’ve recently started noticing this influx of companies.”

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