There is a big push to shift to personalized medicine in countries around the world. But that involves a collection of tasks that are often easier said than done. One example of how processes are being improved is the new labeling for prescription medicines that includes genomic biomarkers. When matched to the results of a patient’s preemptive pharmacogenomics tests, a doctor can quickly identify which drugs will work best, and which are likely to harm that specific person. It also cuts testing costs by a lot.
The choices in tests to match drug choices to specific patients essentially boils down to two: reactive genotyping and preemptive pharmacogenomics testing.
A reactive genotyping test is ordered by a doctor after she or he decides to prescribe a certain medicine, but ideally before the patient takes it. Unfortunately, there is a time lag before the patient is treated and that can be bad if the patient is seriously ill or in pain. And it is inefficient and costly to test for several drugs, one at a time.
Preemptive pharmacogenomics testing involves running a panel of tests prior to a need to prescribe so that the results are part of the patient’s record ahead of time. This is much faster and simpler for physicians to treat patients, providing the drug in question was part of the panel variants pre-test.
In other words, patients can end up pre-tested for some drugs that they never need. However, the authors of one report “found that in 2011 alone, among those with any prescription, 47.6%, 21.2% and 9.8% of patients were prescribed at least one, two, and three medications, respectively, with [preemptive genotyping] PG effects.”
The increased efficiencies and lower costs may be the final determining factors between the two tests.
"Preemptive pharmacogenomics testing versus reactive genotyping is cheaper and ensures results will be available at time of prescribing decisions," said Dr. Mary Relling of St. Jude Children’s Research Hospital and PMWC 2020 PGx Track chair.
Having the genomic biomarker information included on drug labels and drug descriptions in physician references such as the Physicians Desk (Digital) Reference (PDR) makes it even faster and easier for doctors to choose the right medicine for you specifically.
Here’s a short layman’s video explaining how all this works:
In the U.S., the Federal Drug Administration (FDA) now requires pharmacogenomics data to be included in the labeling of drugs. Other countries are expected to soon follow suit. Indeed, some of the data the FDA used is from international sources, and the analysis of genomic biomarker information the FDA conducted is sharable among countries. Even so, for now at least, there are variances between countries in how genomic biomarkers information on drug labels and reference texts are handled.
For example, according to a Nature article: “From the identified 264 FDA approved drugs with pharmacogenomic biomarkers in drug label, 195 are available in Hungary. From them, 165 drugs include pharmacogenomic data disposing 222 biomarkers. Most of them are metabolizing enzymes (46%) and pharmacological targets (41%). The most frequent therapeutic area is oncology (37%), followed by infectious diseases (12%) and psychiatry (9%) … Importantly, US labels present more specific pharmacogenomic subheadings, the level of action has a different prominence, and offer more applicable dose modifications than Hungarians (5% vs 3%). However, Hungarian SmPCs are at 9 oncology drugs stricter than FDA, testing is obligatory before treatment. Out of the biomarkers available in US drug labels, 62 are missing completely from Hungarian SmPCs…”
Pharmacogenomics is important to emergency responders as well in order to avoid adverse reactions and to determine the optimum dose for that patient. The necessity of such life saving information means training programs for clinicians, pharmacists, and first responders are urgently needed so that providers are knowledgeable about the basics -- including interpretations and applications -- of pharmacogenetic testing.
Currently, the FDA’s required genomic biomarkers information for drug labeling includes:
• Drug exposure and clinical response variability
• Risk for adverse events
• Genotype-specific dosing
• Mechanisms of drug action
• Polymorphic drug target and disposition genes
• Trial design features
"The insight of pharmacogenomics and the ability to integrate that knowledge into clinical care via our EHR platform has proven to be a key component of our integrated approach and is generating significant value in patient care,” said Dr. Peter Hulick, NorthShore University HealthSystem and presenter at PMWC 2020 Silicon Valley. NorthShore launched its Pharmacogenomics Clinic in March 2015.
“On average, 97% of patients receive actionable information from a pharmacogenomics gene panel (15-20 genes), and more than half have had variants in multiple pharmacogenomic related genes," Dr. Hulick explained.
Bioinformatics plays an important role in pharmacogenomics in general but also in helping streamline the information to providers.
"We need to make genetic testing and counseling as effortless as possible for our primary care physicians. Even though primary care physicians (PCPs) are very interested in using this information for their patients, they do not want information overload and they do not want to add another five to ten minutes to visits explaining what this means or doesn't mean,” said Dr. Aleks Rajkovic, Chief Genomics Officer at UCSF Health and Chair of Track 3 at PMWC Silicon Valley.
Dr. Rajkovic said that at UCSF where population sequencing is being performed and actionable results are returned, they are minimizing the involvement of primary care physicians and providing backup genetic services. Within UCSF, he says, this will happen with the patient’s consent and the findings will be integrated into electronic medical records in a form that is usable for PCPs.
“This is important for PCPs because at this time they are not going to be interpreting the reports and as such, they are not going to be dealing with variants of unknown significance or other technicalities of genetic testing. Every practice is different, but in general, it is essential that PCP concerns are taken into account in the setting where population-based sequencing is conducted. Moreover, education of PCPs will become essential to improve their participation and empower their ability to incorporate genomic results into the regular care of their patients,” Dr. Rajkovic explained.
The next time you pick up a prescription, check the label. You just might learn a bit more about yourself and the continued breakthroughs in personalized medicine that sometimes appear with little fanfare.