Personalized antiplatelet therapy guided by clopidogrel pharmacogenomics in acute ischemic stroke and transient ischemic attack: A prospective, randomized controlled trial

CYP2C19 and CES1 gene variants affecting clopidogrel metabolism in a South Asian population from Sri Lanka

AIMS

Clopidogrel exhibits substantial variability in therapeutic response, largely contributed by genetic factors. The pharmacogenomic variants data on clopidogrel metabolism in South Asians have been sparsely studied. This study explores the impact of CYP2C19 and CES1 gene variants on clopidogrel metabolism in Sri Lankans, revealing significant pharmacogenomic insights with broader implications for South Asians.

MATERIALS & METHODS

Genotype data were filtered out from an anonymized database of 690 Sri Lankans, and minor allele frequencies (MAFs) were calculated. Five variants of CYP2C19 and one variant of CES1 gene were studied.

RESULTS

Among the five CYP2C19 variants studied, rs12769205 (A>G) and rs4244285 (G>A) had the highest MAF of 42.1% and 42.0%, respectively. The CES1 variant rs71647871 (C>T) showed a MAF of 0.2%. Sri Lankans exhibited significantly higher MAFs for key variants compared to populations such as Europeans, African Americans, and East Asians (p < 0.05).

CONCLUSION

Given that South Asians share genetic similarities, these findings suggest that a substantial proportion of the region's population may also be poor responders to clopidogrel, increasing the risk of adverse outcomes. This highlights the importance of genotype-guided antiplatelet therapy, which could improve clinical outcomes across South Asia amidst rising cardiovascular disease rates.

Impact of CYP2C19 Genotype Status on Clinical Outcomes in Patients with Symptomatic Coronary Artery Disease, Stroke, and Peripheral Arterial Disease: A Systematic Review and Meta-Analysis

BACKGROUND

Clopidogrel is widely used for the secondary prevention of atherothrombotic events in patients with coronary artery disease (CAD), ischemic stroke, and peripheral arterial disease (PAD). CYP2C19 plays a pivotal role in the conversion of clopidogrel to its active metabolite. Clopidogrel-treated carriers of a CYP2C19 loss-of-function allele (LOF) may have a higher risk of new atherothrombotic events. Previous studies on genotype-guided treatment were mainly performed in CAD and showed mixed results.

PURPOSE

To simultaneously investigate the impact of CYP2C19 genotype status on the rate of atherothrombotic events in the most common types of atherosclerotic disease (CAD, stroke, PAD).

METHODS

A comprehensive search in Pubmed, EMBASE, and MEDLINE from their inception to July 23rd 2023 was performed. Randomized controlled trials (RCTs) comparing genotype-guided and standard antithrombotic treatment, and cohort studies and post hoc analyses of RCTs concerning the association between CYP2C19 genotype status and clinical outcomes in clopidogrel-treated patients were included. The primary efficacy endpoint was major adverse cardiovascular events (MACE) and the safety end point major bleeding. Secondary endpoints were myocardial infarction, stent thrombosis, and ischemic stroke.

RESULTS

Forty-four studies were identified: 11 studies on CAD, 29 studies on stroke, and 4 studies on PAD. In CAD, genotype-guided therapy significantly reduced the risk of MACE [risk ratio (RR) 0.60, 95% confidence interval (CI) 0.43-0.83], myocardial infarction (RR 0.53, 95% CI 0.42-0.68), and stent thrombosis (RR 0.64, 95% CI 0.43-0.94), compared with standard antithrombotic treatment. The rate of major bleeding did not differ significantly (RR 0.93, 95% CI 0.70-1.23). Most RCTs were performed in patients after percutaneous coronary intervention (9/11). In stroke, LOF carriers had a significantly higher risk of MACE (RR 1.61, 95% CI 1.25-2.08) and recurrent ischemic stroke (RR 1.89, 95% CI 1.48-2.40) compared with non-carriers. No significant differences were found in major bleeding (RR 0.90, 95% CI 0.43-1.89). In the 6955 patients with symptomatic PAD treated with clopidogrel in the EUCLID trial, no differences in MACE or major bleeding were found between LOF carriers and non-carriers. In three smaller studies on patients with PAD treated with clopidogrel after endovascular therapy, CYP2C19 genotype status was significantly associated with atherothrombotic events.

CONCLUSIONS

Genotype-guided treatment significantly decreased the rate of atherothrombotic events in patients with CAD, especially after PCI. In patients with history of stroke, LOF carriers treated with clopidogrel had a higher risk of MACE and recurrent stroke. The available evidence in PAD with regard to major adverse limb events is too limited to draw meaningful conclusions.

REGISTRATION

PROSPERO identifier no. CRD42020220284.

Cardiovascular Pharmacogenetics: From Discovery of Genetic Association to Clinical Adoption of Derived Test

Recent breakthroughs in human genetics and in information technologies have markedly expanded our understanding at the molecular level of the response to drugs, i.e., pharmacogenetics (PGx), across therapy areas. This review is restricted to PGx for cardiovascular (CV) drugs. First, we examined the PGx information in the labels approved by regulatory agencies in Europe, Japan, and North America and related recommendations from expert panels. Out of 221 marketed CV drugs, 36 had PGx information in their labels approved by one or more agencies. The level of annotations and recommendations varied markedly between agencies and expert panels. Clopidogrel is the only CV drug with consistent PGx recommendation (i.e., "actionable"). This situation prompted us to dissect the steps from discovery of a PGx association to clinical translation. We found 101 genome-wide association studies that investigated the response to CV drugs or drug classes. These studies reported significant associations for 48 PGx traits mapping to 306 genes. Six of these 306 genes are mentioned in the corresponding PGx labels or recommendations for CV drugs. Genomic analyses also highlighted the wide between-population differences in risk allele frequencies and the individual load of actionable PGx variants. Given the high attrition rate and the long road to clinical translation, additional work is warranted to identify and validate PGx variants for more CV drugs across diverse populations and to demonstrate the utility of PGx testing. To that end, pre-emptive PGx combining genomic profiling with electronic medical records opens unprecedented opportunities to improve healthcare, for CV diseases and beyond. SIGNIFICANCE STATEMENT: Despite spectacular breakthroughs in human molecular genetics and information technologies, consistent evidence supporting PGx testing in the cardiovascular area is limited to a few drugs. Additional work is warranted to discover and validate new PGx markers and demonstrate their utility. Pre-emptive PGx combining genomic profiling with electronic medical records opens unprecedented opportunities to improve healthcare, for CV diseases and beyond.

From genes to drugs: CYP2C19 and pharmacogenetics in clinical practice

The CYP2C19 gene is frequently included in different pharmacogenomic panels tested in clinical practice, due to its involvement in the metabolism of a myriad of frequently prescribed medications. Accordingly, CYP2C19 genotyping can promote precise therapeutic decisions and avoid the occurrence of significant drug-drug-gene interactions in the clinical setting. A comprehensive examination of the role of the CYP2C19 gene in real-world medical settings is presented in this review. This review summarizes the most recent information on how genetic variants in CYP2C19 affect drug metabolism and therapeutic outcomes. It goes into the wide range of CYP2C19 phenotypes, with different degrees of metabolizing activity, and their implications for customized medication response through a review of the literature. The review also analyzes the clinical significance of CYP2C19 in several medical specialties, including cardiology, psychiatry, and gastro-enterology clinics, and illuminates how it affects pharmacological efficacy, safety, and adverse effects. Finally, CYP2C19-supported clinical decision-making is outlined, highlighting the possibility of improving therapeutic outcomes and achieving more affordable treatment options, a step towards optimizing healthcare provision through precision medicine.

Clinical pharmacology and pharmacogenomics for implementation of personalized medicine

With the aim of integrating clinical pharmacology with pharmacogenomics and providing a platform to gather clinicians, academicians, diagnostic laboratory personnel and scientists from related domains, the International Conference on Clinical Pharmacology and Pharmacogenomics 2023 (ICCPP 2023) was jointly organized by the Department of Pharmacology, Kasturba Medical College, Mangalore, Manipal Academy of Higher Education, India and the CANSEARCH research platform in Pediatric Oncology and Hematology, University of Geneva, Geneva, Switzerland. The conference was held on 31 August and 1 September 2023, as a continued Indo-Swiss scientific exchange event series. In this report we describe the proceedings of this conference for the benefit of peers who could not attend the conference but are interested in knowing about the scientific program in detail.