A pilot study of the implementation of pharmacogenomic pharmacist initiated pre-emptive testing in primary care

Abstract

Despite the nationwide availability of pharmacogenomic (PGx) guidelines in electronic medication surveillance systems in The Netherlands, PGx guided prescribing is still uncommon in primary care. We set out to investigate the adoption of pharmacist initiated PGx testing in primary care. Community pharmacists were offered a free PGx test covering 40 variants in 8 genes to test patients receiving an incident prescription (IRx) of a selection of 10 drugs. Results of the PGx test along with predicted phenotypes and a therapeutic recommendation based on the Dutch Pharmacogenetics Working Group (DPWG) guidelines were transferred to the pharmacist and physician. Adoption was defined as the percentage of eligible patients that received genotyping. From November 2014-July 2016, 200 patients were included with an adoption of 18.0%. Of the included patients 57.5% received an IRx for atorvastatin, 14.5% started with simvastatin and 28.0% received an IRx for amitriptyline, (es)citalopram, nortriptyline, or venlafaxine. 90% of the patients carried at least one actionable PGx test result in the selected PGx-panel. In 31.0% of the incident prescriptions a combination between a drug with a known genedrug interaction and an actionable genotype was present and a therapeutic recommendation was provided. The provided recommendations were accepted by the clinicians in 88.7% of the patients. Pharmacist initiated implementation of PGx in primary care is feasible, and the frequency of actionable gene-drug interactions for the selected drugs is high.

Assessing the Implementation of Pharmacogenomic Panel-Testing in Primary Care in the Netherlands Utilizing a Theoretical Framework

“…This could be explained by the fact that pharmacists reported on-the-job learning by participating in this implementation study. In addition, 33% of participating pharmacists also had experience from an earlier PGx study [28]. This is in accordance with data showing that providers displayed dramatic increases in personal genomic understanding through program participation [54].…”

“…As part of the U-PGx implementation strategy, enrolling pharmacists were provided with a flexible e-learning program to educate them on using PGx before enrolling patients [31]. Many participating pharmacists previously gained experience with PGx by participating in a PGx pilot study, preceding the current study [28,32].…”

“…As well recognized drug experts and designated HCPs to handle medication surveillance, pharmacists may be better-suited candidates for applying PGx testing than physicians [26][27][28]. A pharmacist-initiated approach to PGx has been proven feasible and is considered promising for the implementation of PGx testing in primary care [28]. In such an approach, pharmacists are responsible for selecting patients eligible for PGx testing and in utilizing their results to guide dose and drug selection at dispensing.…”

Repurposing of Diagnostic Whole Exome Sequencing Data of 1,583 Individuals for Clinical Pharmacogenetics

“…A heterozygosity ratio cutoff set at 0.25 (25% heterozygous variants) resulted in 5.3% of the individuals for whom a CYP2D6 deletion could not be ruled out. This frequency seems concordant with the 1–7% CYP2D6 gene deletions reported in literature for the Dutch population . However, 6 individuals in this group were genotyped heterozygous (e.g., CYP2D6 *1/*4) for at least one of the selected important SNVs in CYP2D6 ( Table ), all of which are exonic variants.…”

“…This frequency seems concordant with the 1-7% CYP2D6 gene deletions reported in literature for the Dutch population. 28 However, 6 individuals in this group were genotyped heterozygous (e.g., CYP2D6*1/*4) for at least one of the selected important SNVs in CYP2D6 ( Table S1), all of which are exonic variants. The presence of heterozygous variants in the CYP2D6 exons indicates that a CYP2D6 gene deletion is highly unlikely indicating that a low ratio of heterozygosity does not necessarily confirm a gene deletion.…”