Evaluating the extent of reusability of CYP2C19 genotype data among patients genotyped for antiplatelet therapy selection

Purpose Genotype-guided antiplatelet therapy is increasingly being incorporated into clinical care. The purpose of this study is to determine the extent to which patients initially genotyped for CYP2C19 to guide antiplatelet therapy were prescribed additional medications affected by CYP2C19. Methods We assembled a cohort of patients from eight sites performing CYP2C19 genotyping to inform antiplatelet therapy. Medication orders were evaluated from time of genotyping through one year. The primary endpoint was the proportion of patients prescribed two or more CYP2C19 substrates. Secondary endpoints were the proportion of patients with a drug–genotype interaction and time to receiving a CYP2C19 substrate. Results Nine thousand one hundred ninety-one genotyped patients (17% nonwhite) with a mean age of 68 ± 3 years were evaluated; 4701 (51%) of patients received two or more CYP2C19 substrates and 3835 (42%) of patients had a drug–genotype interaction. The average time between genotyping and CYP2C19 substrate other than antiplatelet therapy was 25 ± 10 days. Conclusions More than half of patients genotyped in the setting of CYP2C19-guided antiplatelet therapy received another medication impacted by CYP2C19 in the following year. Given that genotype is stable for a patient’s lifetime, this finding has implications for cost effectiveness, patient care, and treatment outcomes beyond the indication for which it was originally performed

Genome-Wide Meta-Analysis of Blood Pressure Response to beta(1)- Blockers : Results From ICAPS (International Consortium of Antihypertensive Pharmacogenomics Studies

Background-There exists a wide interindividual variability in blood pressure (BP) response to beta(1)-blockers. To identify the genetic determinants of this variability, we performed a pharmacogenomic genome-wide meta-analysis of genetic variants beta(1)-influencing blocker BP response. Methods and Results-Genome-wide association analysis for systolic BP and diastolic BP response to beta(1)-blockers from 5 randomized clinical trials consisting of 1254 patients with hypertension of European ancestry were combined in meta-analysis and single nucleotide polymorphisms (SNPs) with P Conclusions-Data from randomized clinical trials of 8 European ancestry and 2 black cohorts support the assumption that BST1 containing locus on chromosome 4 is associated with beta(1)-blocker BP response. Given the previous associations of this region with BP, this is a strong candidate region for future functional studies and potential use in precision medicine approaches for BP management and risk prediction.Peer reviewe

Opportunity for Genotype-Guided Prescribing Among Adult Patients in 11 US Health Systems.

The value of utilizing a multigene pharmacogenetic panel to tailor pharmacotherapy is contingent on the prevalence of prescribed medications with an actionable pharmacogenetic association. The Clinical Pharmacogenetics Implementation Consortium (CPIC) has categorized over 35 gene-drug pairs as "level A," for which there is sufficiently strong evidence to recommend that genetic information be used to guide drug prescribing. The opportunity to use genetic information to tailor pharmacotherapy among adult patients was determined by elucidating the exposure to CPIC level A drugs among 11 Implementing Genomics In Practice Network (IGNITE)-affiliated health systems across the US. Inpatient and/or outpatient electronic-prescribing data were collected between January 1, 2011 and December 31, 2016 for patients ≥ 18 years of age who had at least one medical encounter that was eligible for drug prescribing in a calendar year. A median of ~ 7.2 million adult patients was available for assessment of drug prescribing per year. From 2011 to 2016, the annual estimated prevalence of exposure to at least one CPIC level A drug prescribed to unique patients ranged between 15,719 (95% confidence interval (CI): 15,658-15,781) in 2011 to 17,335 (CI: 17,283-17,386) in 2016 per 100,000 patients. The estimated annual exposure to at least 2 drugs was above 7,200 per 100,000 patients in most years of the study, reaching an apex of 7,660 (CI: 7,632-7,687) per 100,000 patients in 2014. An estimated 4,748 per 100,000 prescribing events were potentially eligible for a genotype-guided intervention. Results from this study show that a significant portion of adults treated at medical institutions across the United States is exposed to medications for which genetic information, if available, should be used to guide prescribing

Prescribing Prevalence of Medications With Potential Genotype-Guided Dosing in Pediatric Patients

Importance: Genotype-guided prescribing in pediatrics could prevent adverse drug reactions and improve therapeutic response. Clinical pharmacogenetic implementation guidelines are available for many medications commonly prescribed to children. Frequencies of medication prescription and actionable genotypes (genotypes where a prescribing change may be indicated) inform the potential value of pharmacogenetic implementation. Objective: To assess potential opportunities for genotype-guided prescribing in pediatric populations among multiple health systems by examining the prevalence of prescriptions for each drug with the highest level of evidence (Clinical Pharmacogenetics Implementation Consortium level A) and estimating the prevalence of potential actionable prescribing decisions. Design, setting, and participants: This serial cross-sectional study of prescribing prevalences in 16 health systems included electronic health records data from pediatric inpatient and outpatient encounters from January 1, 2011, to December 31, 2017. The health systems included academic medical centers with free-standing children's hospitals and community hospitals that were part of an adult health care system. Participants included approximately 2.9 million patients younger than 21 years observed per year. Data were analyzed from June 5, 2018, to April 14, 2020. Exposures: Prescription of 38 level A medications based on electronic health records. Main outcomes and measures: Annual prevalence of level A medication prescribing and estimated actionable exposures, calculated by combining estimated site-year prevalences across sites with each site weighted equally. Results: Data from approximately 2.9 million pediatric patients (median age, 8 [interquartile range, 2-16] years; 50.7% female, 62.3% White) were analyzed for a typical calendar year. The annual prescribing prevalence of at least 1 level A drug ranged from 7987 to 10 629 per 100 000 patients with increasing trends from 2011 to 2014. The most prescribed level A drug was the antiemetic ondansetron (annual prevalence of exposure, 8107 [95% CI, 8077-8137] per 100 000 children). Among commonly prescribed opioids, annual prevalence per 100 000 patients was 295 (95% CI, 273-317) for tramadol, 571 (95% CI, 557-586) for codeine, and 2116 (95% CI, 2097-2135) for oxycodone. The antidepressants citalopram, escitalopram, and amitriptyline were also commonly prescribed (annual prevalence, approximately 250 per 100 000 patients for each). Estimated prevalences of actionable exposures were highest for oxycodone and ondansetron (>300 per 100 000 patients annually). CYP2D6 and CYP2C19 substrates were more frequently prescribed than medications influenced by other genes. Conclusions and relevance: These findings suggest that opportunities for pharmacogenetic implementation among pediatric patients in the US are abundant. As expected, the greatest opportunity exists with implementing CYP2D6 and CYP2C19 pharmacogenetic guidance for commonly prescribed antiemetics, analgesics, and antidepressants

Important preparatory steps and clinical considerations for pharmacogenetics adoption into practice

Genetic influence on medication response has been well documented; yet, the clinical integration of pharmacogenetics has been slow. Lack of knowledge on the fundamentals of pharmacogenetic testing among clinicians and the complexities surrounding test selection, results interpretation, and clinical utility, among others, contribute to this slow adoption. In this paper, we describe integration of pharmacogenetics in the clinic, selection of target population and testing laboratories, team of expertise needed, available resources, and critical considerations for accurate interpretation of test results. We also discuss phenoconversion and pharmacogenetic utility in special populations including pediatrics, pregnant women and transplant patients. Ultimately, it should be observed that pharmacogenetics is an additional piece in the prescribers’ toolbox to guide prescribing decisions. Other intrinsic and extrinsic factors should be considered for more accurate and personalized prescribing practice. This paper aims to guide clinicians with preparatory steps and “clinical pearls” necessary to successfully integrate pharmacogenetics into routine practice

Genomewide association analysis of warfarin dose requirements in Middle Eastern and North African populations

To date, there has been no genomewide association study (GWAS) from the Middle East and North African (MENA) region to identify genetic variants associated with warfarin dose variability using this approach. In this study, we aimed to conduct the first GWAS of warfarin dose requirements in patients from the MENA region. A total of 132 Qatari (discovery) and 50 Egyptians (replication) were genotyped using Illumina Multi-Ethnic Global BeadChip Array. A GWAS was performed on log-transformed weekly warfarin dose in the studied population, adjusting for clinical characteristics and ancestry. The genomewide signals from the discovery cohort were tested in the Egyptian cohort. A GWAS meta-analysis, including the Qatari and Egyptian cohorts, was also performed and the output from this analysis was used in a gene-based analysis. The discovery analysis in Qatari identified five genomewide single-nucleotide polymorphisms (SNPs) in chromosome 16. These signals were replicated in the Egyptian cohort. Combining the two data through a GWAS meta-analysis strengthened the association in chromosome 16 with VKORC1 rs9934438 being the lead genomewide signal (β = −0.17, 6 × 10−15). Other SNPs were identified in chromosome 10 at a p value less than 1 × 10−5. The genetic variants within VKORC1 rs9934438 and CYP2C9 rs4086116 explained 39% and 27% of the variability in the weekly warfarin dose requirement in the Qatari and Egyptians, respectively. This is the first GWAS of warfarin dose variability in the MENA region. It confirms the importance of VKORC1 and CYP2C9 variants in warfarin dose variability among patients from the MENA region.This study was funded by GCC grant through Qatar University (Grant #GCC‐2017‐011)

Real‐world implementation of DPYD and UGT1A1 pharmacogenetic testing in a community‐based cancer center

Abstract We set out to demonstrate the feasibility of pharmacogenetic testing of DPYD and UGT1A1 and explore the clinical benefits in a community‐based cancer center. We conducted a retrospective review of 280 patients who underwent pharmacogenetic testing between November 2020 and May 2023. The primary end points included the percentage of patients with results prior to chemotherapy initiation, percentage of DPYD‐ and UGT1A1‐guided interventions implemented before chemotherapy initiation, and the turnaround time (TAT) for the pharmacogenetics results. Exploratory end points included a comparison of unplanned hospitalizations and treatment interruptions among (1) DPD phenotypes in patients who received fluoropyrimidines and (2) UGT1A1 phenotypes in patients who received irinotecan ± fluoropyrimidines. We evaluated cancer progression among patients who received DPYD‐guided dose reductions in the curative setting. More than 75% of patients had results prior to initiation of chemotherapy and 61.5% of the actionable interventions were implemented before chemotherapy, with a median TAT of 7 calendar days (IQR 5–8 calendar days). A non‐significant higher percentage of unplanned hospitalizations and treatment interruptions occurred among patients with normal DPYD compared with patients with DPYD‐guided dose reductions. A non‐significant higher frequency of treatment interruptions and dose reductions were observed in UGT1A1 intermediate metabolizer (IM) compared with UGT1A1 normal metabolizer (NM). None of the patients who received DPYD‐guided dose reductions in the curative setting experienced progression after a median follow‐up of 342 days. The real‐world evidence generated from this study demonstrates the feasibility of pre‐chemotherapy pharmacogenetic testing of DPYD and UGT1A1 in a community‐based cancer center

Multi-site Investigation of Genetic Determinants of Warfarin Dose Variability in Latinos

We conducted a multi-site investigation of genetic determinants of warfarin dose variability in Latinos from the U.S. and Brazil. Patients from four institutions in the United States (n = 411) and Brazil (n = 663) were genotyped forVKORC1c.-1639G> A, commonCYP2C9variants,CYP4F2*3, andNQO1*2. Multiple regression analysis was used in the U.S. cohort to test the association between warfarin dose and genotype, adjusting for clinical factors, with further testing in an independent cohort of Brazilians. In the U.S. cohort,VKORC1andCYP2C9variants were associated with lower warfarin dose (beta = -0.29,P < 2.0 x 10(-16); beta = -0.21,P = 4.7 x 10(-7), respectively) whereasCYP4F2andNQO1variants were associated with higher dose (beta = 0.10,P = 2 x 10(-4); beta = 0.10,P = 0.01, respectively). Associations withVKORC1(beta = -0.14,P = 2.0 x 10(-16)),CYP2C9(beta = -0.07,P = 5.6 x 10(-10)), andCYP4F2(beta = 0.03,P = 3 x 10(-3)), but notNQO1*2(beta = 0.01,P = 0.30), were replicated in the Brazilians, explaining 43-46% of warfarin dose variability among the cohorts from the U.S. and Brazil, respectively. We identified genetic associations with warfarin dose requirements in the largest cohort of ancestrally diverse, warfarin-treated Latinos from the United States and Brazil to date. We confirmed the association of variants inVKORC1,CYP2C9, andCYP4F2with warfarin dose in Latinos from the United States and Brazil.Open access journalThis item from the UA Faculty Publications collection is made available by the University of Arizona with support from the University of Arizona Libraries. If you have questions, please contact us at [email protected]