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Pharmacogenomics in the ambulatory care setting bodes well for patients, providers
Michelle Powell 1302

Pharmacogenomics in the ambulatory care setting bodes well for patients, providers

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Loren Bonner

New research continues to support the integration of pharmacogenomics into clinical practice.

“Pharmacogenomics is the lowest hanging fruit in medicine today,” said Burns C. Blaxall, PhD, senior author of a paper in JAPhA about implementing comprehensive pharmacogenomics in a community hospital–associated primary care setting.

According to the research, which was published in September 2022, pharmacogenomics-certified ambulatory care pharmacists embedded within primary care offices recommended a change in medication 82% of the time when an intervention was actionable.

“Implementation science matters,” said Blaxall, who is executive director of Precision Health at the Christ Hospital Health Network in Cincinnati.

Although many drug–gene interactions are known today, they are not yet routinely addressed in clinical practice.

Blaxall and his team at Christ Hospital wanted to determine the impact of pharmacogenomic services within their primary care offices using embedded, board certified, pharmacogenomics-certified ambulatory care pharmacists; a pharmacogenomics risk evaluation tool; a comprehensive pharmacogenomics gene panel; and a clinical decision support tool integrated in the electronic medical record.

They found that the underlying reasons for recommending therapy alterations were ineffective therapy (43%), prevention of adverse drug reactions (34%), or observation of an adverse drug reaction (13%).

Frontlines of pharmacogenomics

The first pharmacist was embedded in primary care offices within the Christ Hospital Health Network in 2019. Today, there are 11 board-certified, pharmacogenomics-certified ambulatory care pharmacists—likely more than any other health system, according to Blaxall.

Each pharmacist is embedded directly into the primacy care clinic, physically located in the offices, and assisting with chronic disease management, medication therapy management, and pharmacogenomics. The pharmacists serve as medication and pharmacogenomic experts. They recommend pharmacogenomic testing when appropriate, interpret results, and provide subsequent therapy recommendations to prescribers within and beyond primary care.

“We knew that training every doctor in our health network to do pharmacogenomics was a fantasy, and we also know that individual gene–drug practice alerts in the electronic medical record are marginally effective, but a specialized group of ambulatory care pharmacists were really the front lines for our success,” Blaxall said.

Another reason to have pharmacists lead this effort is that primary care physicians or specialists may only be prescribing a small number of the many medications a patient is taking. A pharmacist can take a broader and all-encompassing look at a patient’s medication list, acting as the central person of the health care team to help optimize all the patient’s medications.

A pharmacist can take a broader and all-encompassing look at a patient’s medication list, acting as the central person of the health care team to help optimize all the patient’s medications.


Pharmacogenomics-certified pharmacists

In order to have a successful pharmacogenomics program, Blaxall said pharmacists need to be board-certified in their practice area with additional training and certification in pharmacogenomics.

Board certification is administered through the Board of Pharmacy Specialties, the only board-certifying body for pharmacists in the United States. Pharmacogenomic certification for Christ Hospital pharmacists was administered through the American College of Clinical Pharmacy or the American Society of Hospital Pharmacists, two of several bodies offering such certification.

Blaxall said it’s also imperative to test with the broadest pharmacogenomics panel possible. Research supports this, too. A vast majority of pharmacogenomic-guided treatment recommendations can be missed if only a single-gene or disease-specific panel is used.

“How unfortunate would it be if you had tried to optimize a patient’s antidepressant medication, but they remained depressed because of another poorly treated chronic disease?” Blaxall said. A recent study published in The Lancet further validates a panel-based approach with a multicenter trial in seven countries showing a 30% reduction in clinically significant adverse drug events in just 12 weeks.

Pharmacogenomics testing doesn’t always need to have big implications either.

“Sometimes it’s the simple cases,” Blaxall said. For example, he recalled how one patient of theirs had suffered from acid reflux for 12 years while trying various treatments that were not working. “This patient saw three specialists, was scoped four times, tried six medications, with no relief of symptoms. Fortunately, she was randomized to our clinical trial. Two days after her pharmacogenomic testing results came back, the patient was prescribed the right medication and remains entirely symptom-free over a year later.”

Blaxall hopes their research can highlight to others that a pharmacogenomics program within primary care is not only possible, but can be highly effective.

“Four years ago, we had nothing,” Blaxall said. “The path to success is C-suite support, robust IT-level integration, and of course, board-certified, pharmacogenomics-certified pharmacists embedded in primary care offices.” ■


What is PGx?

Pharmacogenomics (PGx) refers to genetic determinants of drug response and uses candidate genes to study gene–drug interactions. PGx studies how germline (i.e., inherited) mutations affect response to drugs.

Virtually all of us carry a clinically relevant variant of one or more pharmacogenes. The pharmacokinetic, pharmacodynamic, and human leukocyte antigen genetic variants are associated with variability in drug response.

The field of PGx is fueled by the latest advances in artificial intelligence that combine pharmacology, genetics, and psychiatry for greater precision in diagnosis and treatment, allowing individualized drug selection and clinical practice. ■


The Clinical Pharmacogenetics Implementation Consortium

One barrier to putting pharmacogenetic testing into practice in the clinic setting is the difficulty translating genetic laboratory test results into actionable prescribing decisions for affected drugs.

The Clinical Pharmacogenetics Implementation Consortium, or CPIC, is an international consortium of individual volunteers and a small dedicated staff who are facilitating use of pharmacogenetic tests for patient care.

CPIC’s goal is to address this barrier to clinical implementation of pharmacogenetic tests by creating, curating, and posting freely available, peer-reviewed, evidence-based, updatable, and detailed gene/drug clinical practice guidelines.

More can be found at ■



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