Pharmacogenomics in Clinical Practice: Where Do We Go From Here?

In an interview with Medscape, Mark J. Ratain, MD, Professor of Medicine at the University of Chicago and Founding Director of the University's Center for Personalized Therapeutics, pointed out that pharmacogenomic testing needs to move from the realm of reflex lab testing to part of the physical exam….

“I think we need to take genetic testing out of the domain of laboratory testing and move it to the domain of physical examination. It can then be one more piece of information for the physician to consider and we wouldn't need to focus on the cost.”

“There are a lot of things we do during a physical examination that have never been demonstrated to be cost-effective. Physicians look at their patients' toes as part of an annual physical. Have you ever seen a study that shows that looking at your toes is cost-effective?”“We need to conceptualize genetic testing as a part of the physical exam rather than as a laboratory test that needs to be ordered so you can have the information at the time you are seeing the patient. For example, if you're starting a patient on warfarin, or you are considering whether to start him on warfarin, and you already know that he is going to metabolize warfarin a lot more slowly or that he's going to be a lot more sensitive to it, you can take that into account in the same way you would probably use a lower dose if your patient were frail or elderly. That is where I think the field needs to move.”

“The solution is one that we are piloting here, which is to genotype all patients for all polymorphisms that may affect drug response. You'll then have the results when you need them and your costs will be much lower than doing each test as a one-off laboratory test.
In the current system, you see the patient and want to prescribe a drug, and you say to yourself, ‘Maybe I should order a pharmacogenetic test. But I don't know how to do that, I don't know how long it is going to take to get results, and I don't know if my patient is going to get reimbursed for it. Oh, who cares. I am just going to prescribe the drug.'

“Unless someone says that you can't prescribe the drug without doing the test, or unless we change the way we look at how pharmacogenomic testing should be incorporated into clinical practice, the system is unlikely to change.”

Bringing Personalized Prescribing to the Community Pharmacy

An interview with Brian Hocum, PharmD of Wasem’s Pharmacy who has recently made personalized prescribing available to at-risk customers.

Why do you think genetics is important?
I tell my patients that through DNA technology, we are able to determine what type of drug metabolizer they are. I explain how this information can be used to help predict if they are at risk of having bad reactions to drugs (too much drug exposure) or poor response to drugs (too little exposure to the medication). Genetics is important because it allows Health Care Providers, like myself, to predict who will have “bad reactions” or “poor responses” to medications.

How would you define personalized prescribing in your own words?
‘Personalized prescribing” is the analysis and incorporation of patient specific factors (i.e. CYP450 metabolizing capacity–derived from DNA testing) prior to prescribing, dispensing and/ or choosing new medications (including OTC, vitamins, herbals) and doses. While we typically think of “prescribing” as something only Physicians do, I feel “personalized prescribing” is something we can all embrace; Physician, Pharmacist & Patient.

Why did you decide to launch this program at Wasem’s?
As a Pharmacist working in a community pharmacy, my number one goal is to serve the patients of the community. Our services are what bring patients into the store and they are what keep them coming back for years. Keeping patients safe through more informed medication and dose choices is the best service we can provide and “personalized prescribing” is the best tool I know of to do so.

What efforts have you made to educate physicians and patients in your community about personalized prescribing?
We have in the past and continue to educate the community through newspaper advertisements, co-marketing posters and speaking with community volunteer groups like the Rotary, Lion’s club and retirement centers.

Since pharmacists are able to order laboratory tests in Washington State for the purpose of monitoring drug therapy, I often find that the prescribers are unacquainted with “personalized prescribing.” I send them a fax describing what the genetic results mean, and any alternate medications or dose adjustments that they might considered based on the results. The response has been all positive. Doctors are noting the recommendations in their patient charts. I plan to host a dinner soon for Health Care Providers to educate them about “personalized prescribing.”

You have now made several successful interventions on a patient’s behalf; can you share one of these stories?
Yes, here is one of the first testimonials I received after a successful pharmacogenetic intervention. This patient struggled with adverse drug reactions her whole life, and was relieved that science and technology are finally beginning to understand and incorporate “personalized prescribing:”

“Thank you so much for guiding me through the new way to approach medication. Armed with the letter to my health care provider, I feel confident that finally my doctor will be able to adjust some of my medications. Maybe some day genetic testing will be a routine procedure before prescribing meds. How much misery and money could be saved if we get it right the first time…”

A Family Battle to Overcome Bad Genes for Drug Metabolism

This is an abridged version of an article Tom Carlson, owner of HostasDirect and IdealGardenMarkers, is sending to all of his subscribers because he is a staunch advocate for personalized medicine based upon almost tragic personal experiences.

It has been known for years that people react differently to medications. There is more than a 50% chance that you have an easily diagnosed drug metabolizing enzyme problem, a genetic mutation that causes 100,000 deaths and 2,200,000 serious drug reactions in the U.S. every year. If you know and understand your enzyme situation, you can learn which prescription drugs are best and worst for you. A simple genetic test can mean the difference between a drug that makes you well and one that gives you a toxic reaction or has no effect at all. Despite these tests being around for the last few years, a recent study found that only "1 in 4 physicians had any education in the use of genetic testing to guide medical decisions,” and many people are unaware of how far personalized medicine has come.

My family and I have experienced first-hand how pivotal this information is. We have all been tested, and it has been very influential in improving our health care. Members of my family have suffered and almost died from being prescribed medications that did not match their unique and genetically determined drug metabolizing enzymes. I am not in any way affiliated with the genetic testing industry; this is simply something I am passionate about and I feel that it is my responsibility to share this knowledge with you.

My dad almost died from a bad drug-gene interaction in 2008 caused by a common prescription pain killer. Even though he explained to his outstanding health care providers that, like 10% of the population, he is a poor metabolizer of the CYP2D6 enzyme, he was still prescribed the wrong pain medication after surgery. His caregivers did not understand the drug-metabolizing enzyme information he provided and he was prescribed a medication that is solely metabolized by CYP2D6. He rapidly became very sick, and experienced no pain relief. I thought he was going to die in front of me. As he was suffering, I went on the web and learned that thousands have died from the combination of drugs and being a CYP2D6 poor metabolizer.

My mother also had a problem with Coumadin, a common blood thinner, which could have been very serious. Like 35% of the population, she is an intermediate metabolizer of the CYP2C9 enzyme, which metabolizes the blood thinner. She told her caregivers about her enzyme deficiency, but they did not know of the tests or what my mom’s meant. Worse yet, they did not tell her they did not understand what she told them. These caring, smart, hardworking people proceeded to give her way too much blood thinner for her enzyme situation. When she returned to get her blood checked, they discovered that her blood had become dangerously thin, and there was a risk that she could bleed to death.

These incidences–and others I can’t name here–could have, and should have, been prevented!

Please realize I am not a physician and take no liability for your decisions. Talk to your doctors, pharmacists, and nurses and find out if they are familiar with this testing. I have talked to many highly regarded physicians that were not familiar with these tests. They greatly appreciated the information I shared, and some even changed how they prescribed medications to members of my family. One physician told me, “Of course we have seen different results in patients given the same medications, but we have never understood why–this makes total sense. Thanks for letting me know.”

Please pass this information along–knowledge and understanding of these tests needs to get to the public and medical community. You might save or improve a life!

Genelex has created a new web page at http://www.healthanddna.com/drug-safety-dna-testing/stories.html called Real People, Real Stories to help raise awareness.

Do you have a story to share? Email info@genelex.com.