Personalized Medicine: The Future of Genetic Testing?

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You’re feeling under the weather, with a cough that just won’t go away, so you decide to visit your doctor.  After a few minutes of one-on-one time, with some poking and prodding, you may be walking out of the office with a prescription in hand and on the way to feeling better.  How much more personal does it get? Perhaps not surprisingly, it can get a lot more personal, and it has nothing to do with your doctor, and everything to do with science.

In our current system of medicine, your treatment plan has very little to do with you specifically; most likely it is the exact same treatment your doctor would give to anyone with the same condition.  Medicine today is based on “standards of care,” the most prudent course of prevention or treatment for the general population.  With medication treatment for depression, for example, those standards may mean treatment with an SSRI (selective serotonin reuptake inhibitor), followed by a second trial if the first one fails. If the second treatment fails, doctors and patients move on to the next one and the next in a trial and error approach.

This trial and error approach can be extremely frustrating to patients and doctors alike, as medication after medication is attempted, and failed.  Fortunately, genetic sequencing and recent advances in molecular biology may provide a better way.  Researchers, clinicians, and an increasing number of patients are calling for a more personalized approach aimed as much at preventing disease as it is at tailoring treatment once it’s there.  Personalized medicine that is truly personal–an approach based on the predispositions written into your genome at birth.In the case of cancer, the disease has its own genetic makeup, lending each tumor a unique character with differing tendencies and vulnerabilities.

One of the areas in which genomic medicine is especially promising is in the arena of cancer.  Not only does each individual have their own personal genetic markers, but in the case of cancer, the disease has its own genetic makeup, lending tumor a unique character with differing tendencies and vulnerabilities. This uniqueness allows for specific targeting and treatment of different tumor types.

How might this genomic medicine work in the case of cancer?  Genetic sequencing is utilized to find the order of nucleotides in a given DNA molecule and can be used to determine a patients cancer type and to determine what courses of treatment are appropriate for a patient. Next generation sequencing (NGS) utilizes high-throughput sequencing platforms, and while not generally considered a superior form of genetic sequencing it is starting to be considered in pharmaceuticals to be a vital tool for the future of pharmacological discovery.  NGS has many advantages over first-generation sequencing, including the fact that a smaller sample size is all that is required to sequence the BRCA genes (500 ng when using NGS compared to 3μg using the Sanger method of sequencing). 

Cancer is a particularly insidious disease due to its primarily unnoticeable spread until symptoms become life disrupting, however using blood tests and genome sequencing, we may be able to develop a way to detect cancer in patients before the symptoms begin to manifest. This is only one application of genetic sequencing but is the most applicable one to the average person given the way cancer attacks indiscriminate of social status, race, sex or geographical location.  Other applications, while unexpected, include anxiety and depression and the side effects that medications may or may not present in a given patient. 

“I can look at a patient’s CYP450 numbers and then look at the collective patient data of a medication I’m considering to see how that medication interacted with people who had a similar CYP450 profile.” – Dr. Barnell Phillips 

Tumor markers can also be used to indicate the progress of treatment; whether a cancer is being eradicated or worsening, without using invasive tests or costly methods.  The practical applications of genetic sequencing are still being researched, but personalized medicine is gaining popularity among a diverse population and may be the future.  In 2015, the Regeneron Genetics Center had already sequenced the DNA of more than 35,000 Geisinger patients. Databases like these have huge implications for clinical trials, which sometimes struggle to find patients fitting the narrow parameters required, and with rare diseases, it can be even harder. 

“You no longer have to find that one rare family in Italy, because it’s just in the database.”  -Dr. George Yancopoulos, Regeneron

Recent advances in genomic based medicines have targeted a wide variety of diseases.  Regeneron and Sanofi were recently expected to win approval for a cholesterol lowering drug that blocks the PCSK9 gene.  Other companies using gene sequencing for a variety of uses include Amgen and Pfizer. Amgen purchased Decode Genetics in 2012, and discovered a new gene mutation that correlates with Alzheimers risk and confirmed the role of a mutation in two other diseases. Pfizer has a deal with genetic testing company 23andMe to further study lupus.  These are only a few of the recent advances, the list continues to grow as patients and clinicians demand more cost effective and targeted therapies.

In the healthcare industry, drug manufacturing companies stand to gain tremendously from utilizing gene sequencing, standing only behind the patients. Although genes are not destiny, they do provide information that can lead us to make more informed decisions about our health and healthcare choices, decisions that can change the future.  

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