There are currently more than 40 drugs approved to treat depression. For many patients, it can be an experience in trial and error to determine what drug or combination works the best with the fewest side effects. In an ideal situation, your genetic profile could inform your doctor the best drug, along with the best dose. The good news is that this scenario is a growing and exciting field of research called pharmacogenomics.
Pharmacogenomics describes how your genetic make-up could affect your response to certain drugs. This relatively new field combines the study of pharmacology with genomics, allowing researchers and clinicians to understand how individual genetics can be used to determine the best treatment in regards to efficacy, safety and other factors. Pharmacogenomics has found uses in cardiology, psychiatry, and oncology, among other therapeutic areas.
There are nearly 400 drugs approved by the U.S. Food and Drug Administration (FDA) that use pharmacogenomics in prescribing. In addition, there are non-human genetic biomarkers, including those found in your microbiome, that can affect how your body reacts to drugs like antibiotics.
One example of using pharmacogenomics in treatment is the use of CYP2D6, an enzyme metabolized in the liver. There are over 100 variations of this enzyme, with many dependent on ethnicity, that can affect toxicity and efficacy. For example, drugs that treat high blood pressure and depression can be personalized dependent on CYP2D6 pharmacogenetics, such as the dose, response and toxicity risk. It can also affect the efficacy of the breast cancer drug tamoxifen and the body’s metabolizing of codeine to morphine.
Psychiatry is one field where pharmacogenomics is gaining increasing attention. The Clinical Pharmacogenetics Implementation Consortium recommends clinicians not prescribe certain drugs to patients who carry variations of CYP2D6 or CYP2C19 associated with rapid or slow metabolism of these drugs. However, few clinical guidelines exist on when and how to provide patients genetic testing to determine if they carry these variations. It’s estimated that at least 8% of patients would benefit from this type of testing. However, research is still ongoing, and the relationship between these genetic variations and the effectiveness of antidepressants has not been confirmed.
While this medical information is useful when clinicians are prescribing medicine for their patients, direct-to-consumer genetic testing companies are now providing pharmacogenomic results directly to individuals.
In late 2018, the FDA approved the first commercial pharmacogenomics test, however, it cautioned that the test is not intended to provide information on an individual’s response to a specific medication or be used to make treatment decisions. Almost immediately, the FDA issued a statement on direct-to-consumer genetic tests that provide pharmacogenomic results, essentially recommending against changing treatment decisions based on results from these types of genetic tests.
The FDA is now looking at regulating consumer companies in this field, especially as more and more companies provide pharmacogenomic results in their client reports. The federal agency is concerned that as this field grows, patients may receive inaccurate or incomplete results that lead them to make poor or even harmful treatment decisions. In April, the FDA issued a warning letter to one company it said was illegally marketing its pharmacogenomics test to the public.
“We are particularly concerned about pharmacogenetic tests that claim to predict patients’ responses to specific medications where such claims have not been established and are not described in the drug labeling and continue to warn patients and health care professionals that they should not rely on these tests for treatment decisions, ”said Dr. Jeff Shuren, director of the FDA’s Center for Devices and Radiological Health, in a recent press release from the FDA.
Similar to releasing genetic results without the nuances of a genetics counselor to help interpret the results, the agency is concerned patients will make treatment decisions based on tests that could be inaccurate.
However, several groups are questioning the FDA’s recent actions.
Four mental health advocacy groups recently sent a joint letter to the FDA citing that this recent decision could impede innovation and inflict harm on patients. Health care providers and patients, they say, should have all of the information, tools and resources to advocate for the best treatments for themselves. In addition, the American Clinical Laboratory Association issued a letter to the FDA, sharing that the recent restrictions could increase medical costs and impact care.
While the use of marketing pharmacogenomics is being debated, the obvious answer is the need for more confirmatory research where pharmacogenomics is being used in clinical decisions. That’s where LunaDNA can help.
Individuals who securely and privately share their genetic results in the LunaDNA platform can contribute to research, which may include pharmacogenomic. Users can be rewarded for their participation in crowd-sourcing science, while helping to advance discoveries in this field.