Prescribing is a complex process with multiple factors to consider on top of the 3 primary questions about effectiveness, harm, and cost. Pharmacogenetics has put this complexity under the spotlight and prompted educational programs and the development of new clinical decision support systems.
In the United States, 46 million adverse drug reactions (ADRs) are reported each year leading to 1.3 million emergency department visits and a cost of billions to the health care system. The time to implement pharmacogenetics (PGx) for clinical decision support is now.
Depending on an individual’s genes and other factors, some medications may work more effectively, less effectively, or cause adverse effects. Technologies exist that use PGx and other information to help identify safer and more effective medication options for an individual.
Almost everyone has a genetic variant associated with documented drug-gene interactions. The drugs impacted by these genetic variations are very commonly used. A large number of rigorous evidence-based guidelines about drug-gene interactions combined with the prevalence of these PGx variations has reached a level such that the United Kingdom is planning how to make it available to everyone.
As an example of PGx implementation, the United Kingdom has developed a comprehensive strategic plan. A report from the Royal College of Physicians and British Pharmacological Society joint working party, entitled “Personalised Prescribing, Using Pharmacogenomics to Improve Patient Outcomes,” provides evidence on the use of PGx information and the template for widescale implementation.
The challenge is making sure that genetic information is available to the health care professionals wherever and whenever they are prescribing, in a format that is usable, and that they know how to use it. It has to be available in primary and secondary care settings, as well as in specialized centers. Two key parts of the solution are education and systemwide implementation.
Once the UK National Health Service (NHS) has determined the PGx test panel, it will be included in the National Genomic Test Directory, which will outline eligibility, testing scope, and actionability within the whole of the UK NHS. Building on the success of the 100,000 Genomes Project, NHS England launched the Genomic Medicine Service (GMS) in October 2018 to further embed genomics into the NHS.
Prior to this, genomic testing facilities across England were reconfigured into 7 regional genomic laboratory hubs (GLHs) to consolidate and enhance genomic testing capacity and capability. The GLHs provide a national testing network that underpins the GMS as it strives to meet its commitment to the NHS Long Term Plan to sequence 500,000 whole genomes from patients as part of their routine NHS care by 2023-2024.
Some of the key tenets of the UK plan include, but aren’t limited to:
Any first step in the implementation of pharmacogenomics must be accompanied by a targeted education and training package. Given that most prescribing occurs in primary care, primary care doctors and pharmacists will be an essential component of this interdisciplinary PGx service.
The education must be tailored to the clinical setting and the health care professional. It is not a genomics course but knowledge about PGx variants and how they can be used for those patients seen by that clinic/hospital/health network organization. In our experience, an hour of education is sufficient for people to start using this knowledge.
At the heart of many of the steps identified by the NHS is Clinical Decision Support System (CDSS). The CDSS should help health care professionals identify medication options and doses for that patient. In the United States, there is little PGx CDSS in the EHRs used daily by health care professionals.
Implementation of PGx informed CDSS can be scaled incrementally. Health care professionals are used to lab reports, and these are the first step of the CDSS implementation process. A report describes the potential drug-gene interaction with drugs. In a sense it is no different from looking up a potential drug-drug interaction showing a scale of the clinical impact of the interaction.
However, the evidence is growing for drug-gene interactions as it is for drug-drug interaction, so a static printed report is not optimal. The PGx information must be available wherever the patient is being seen for prescriptions from the community pharmacist to the hospital, so some secure cloud process that ensures patient privacy is needed. The technology for this exists in banking, so it is feasible.
An alert at the time of prescribing, after patient shared decision-making has resulted in a choice of medication, is not the most helpful decision support. For drugs with drug-gene interactions, the second phase of the decision support should consider not only the PGx, but also the renal system, liver, other drugs, and other conditions where appropriate. The impact of all these factors should be displayed to the health care professional before discussing the options with the patient.
For the most frequently seen conditions, a PGx decision support system should identify the guideline-based medication options available considering all the relevant patient characteristics. CDSS software can do all this in seconds providing the health care professional with a list of medication options for the condition, based on all the patient variables. Entering those variables can be done in a few minutes but it is more efficient if the decision support is integrated with the pharmacy management system or the EHR.
Prescribing is a complex process with multiple factors to consider on top of the 3 primary questions about effectiveness, harm, and cost. PGx has put this complexity under the spotlight and prompted educational programs and the development of new clinical decision support systems. The use of PGx is a step on the path to safer, more effective prescribing.