Pharmacogenomics of anti-platelet therapy: how much evidence is enough for clinical implementation?

Effect of age on the efficacy and safety of Panax notoginseng saponins in acute ischemic stroke: a prespecified secondary analysis of the PANDA study

BACKGROUND

The therapeutic utility of Panax notoginseng saponins (Xuesaitong soft capsules) for patients with acute ischemic stroke (AIS) was previously demonstrated through the PANax notoginseng Saponins Treatment of aDults with ischemic stroke in ChinA (PANDA) trial, revealing significant gains in functional independence compared to placebo. However, the related variation of older age accepted as the predictors of poor outcome, in response to Panax notoginseng saponins remains unexplored.

METHODS

We conducted a prespecified analysis of the PANDA trial to evaluate the effect of age on the efficacy and safety of Xuesaitong soft capsules. A multivariable logistic and Cox regression analysis with an interaction term was used to determine whether age (< 65 years vs. ≥ 65 years) affected the treatment effect. The primary outcome of this study was functional independence at the 3-month follow-up, as indicated by a modified Rankin Scale score (mRS) ranging from 0 to 2.

RESULTS

Between July 1 th, 2018, and June 30 th, 2020, a total of 3072 patients were recruited from 67 medical centers in China. Of these, 2966 patients were incorporated into the intention-to-treat (ITT) analysis and subsequently categorized into two age-based subgroups: (1) 1788 patients (60.28%) aged less than 65 years and (2) 1178 patients (39.72%) aged 65 years or older. Age significantly influenced the proportion of AIS patients attaining functional independence within three months [aged ≥ 65 years, adjusted odds ratio (aOR): 3.15, 95% CI: 2.13-4.67, P < 0.0001; aged < 65 years, aOR: 1.84, 95% CI: 1.33-2.54, P = 0.0002; P for interaction = 0.027]. Notably, a significant interaction was detected between age categories and treatment, with a greater likelihood of achieving functional independence among AIS patients aged ≥ 65 years. Regarding the primary safety outcome, which measured the rate of serious adverse events (SAEs) at 3 months, no significant difference was detected between the treatment and placebo groups across both age categories (aged ≥ 65 years, aOR: 0.32, 95% CI: 0.06-1.69, P = 0.181; aged < 65 years, aOR: 1.76, 95% CI: 0.41-7.47, P = 0.444; P for interaction = 0.132).

CONCLUSIONS

This prespecified secondary analysis suggests that AIS patients can potentially benefit from Xuesaitong treatment in achieving functional independence, irrespective of age. Furthermore, older individuals may experience more substantial clinical benefits from Xuesaitong soft capsules for AIS.

Age and outcomes following personalized antiplatelet therapy in chronic coronary syndrome patients: a post hoc analysis of the randomized PATH-PCI trial

It is particularly important to establish more effective and safer antiplatelet treatment strategies according to age. The present subanalysis of the PATH-PCI trial was to determine the safety and efficacy of any dual-antiplatelet therapy (DAPT) strategy in different age groups. We randomized 2285 chronic coronary syndrome (CCS) patients undergoing percutaneous coronary intervention (PCI) into a standard group or a personalized group from December 2016 to February 2018. The personalized group received personalized antiplatelet therapy (PAT) based on a novel platelet function test (PFT). The standard group received standard antiplatelet therapy (SAT). Then, all patients were divided according to age (under the age of 65 years and aged 65 years or over) to investigate the association and interaction of age on clinical outcomes at 180 days. In the patients under the age of 65 years, the incidence of NACEs was decreased in the personalized group compared to the standard group (5.1% vs. 8.8%, HR: 0.603, 95% CI: 0.409-0.888, P = .010). The rates of MACCEs (3.3% vs. 7.7%, HR: 0.450, 95% CI: 0.285-0.712, P = .001), MACEs (2.2% vs. 5.4%, HR: 0.423, 95% CI: 0.243-0.738, P = .002) also decreased. We did not find a significant difference in bleeding between the groups. In the patients aged 65 years or over, no difference in the primary endpoint was found (4.9% vs. 4.2%, P = .702), and comparable rates of survival were observed with the two strategies (all Ps > 0.05). The present study shows that PAT according to PFT was comparable to SAT at the 180-day follow-up for both ischemic and bleeding endpoints in CCS patients aged 65 years or over who underwent PCI. In patients under the age of 65 years, PAT can reduce ischemic events but does not increase bleeding, and it is an effective and safe treatment strategy. It may be necessary for young CCS patients after PCI to undergo PAT early after PCI.

Structural characterization of the optical isomers esomeprazole and omeprazole using the JADER and FAERS databases

BACKGROUND

It is unclear whether the s (-) form of esomeprazole (EPZ) has an improved safety profile when compared with its racemic form omeprazole (OPZ). We assessed the potential complications of these optical isomers when combined with cilostazol, clopidogrel, and prasugrel, which are frequently used concomitant medications.

METHODS

Using two adverse event spontaneous reporting databases, Japanese Adverse Drug Event Report (JADER) and FDA Adverse Event Reporting System (FAERS), adverse event names for hemorrhage, venous/arterial embolization, and thrombus were obtained from the Medical Dictionary for Regulatory Activities. Reported odds ratios were calculated using a 2 × 2 contingency table, and a signal was considered present if the lower limit of the 95% confidence interval was >1.

RESULTS

In combination with cilostazol, a hemorrhagic signal for OPZ in JADER and arterial emboli and thrombus signals for EPZ were detected in both databases. In combination with clopidogrel, OPZ showed arterial emboli and thrombus signals in JADER and venous/arterial emboli and thrombus signals in FAERS, while EPZ displayed arterial emboli and thrombus signals in FAERS. In contrast, when in combination with prasugrel, there were no adverse event signals in either database.

CONCLUSION

This study has confirmed using big data, that EPZ, the optical isomer and racemic form of omeprazole, has the beneficial characteristics of being less sensitive to CYP, as was intended by its design.

Opportunities to implement a sustainable genomic medicine program: lessons learned from the IGNITE Network

Purpose

While there is growing scientific evidence for and significant advances in the use of genomic technologies in medicine, there is a significant lag in the clinical adoption and sustainability of genomic medicine. Here we describe the findings from the National Human Genome Research Institute’s (NHGRI) Implementing GeNomics In pracTicE (IGNITE) Network in identifying key constructs, opportunities, and challenges associated with driving sustainability of genomic medicine in clinical practice.

Methods

Network members and affiliates were surveyed to identify key drivers associated with implementing and sustaining a genomic medicine program. Tallied results were used to develop and weigh key constructs/drivers required to support sustainability of genomic medicine programs.

Results

The top three driver–stakeholder dyads were (1) genomic training for providers, (2) genomic clinical decision support (CDS) tools embedded in the electronic health record (EHR), and (3) third party reimbursement for genomic testing.

Conclusion

Priorities may differ depending on healthcare systems when comparing the current state of key drivers versus projected needs for supporting genomic medicine sustainability. Thus we provide gap-filling guidance based on IGNITE members’ experiences. Although results are limited to findings from the IGNITE network, their implementation, scientific, and clinical experience may be used as a road map by others considering implementing genomic medicine programs.

The impact of real-world cardiovascular-related pharmacogenetic testing in an insured population

BACKGROUND

Pharmacogenomics is intended to help clinicians provide the right drug to the right patient at an appropriate dose. However, limited evidence of clinical utility has slowed uptake of pharmacogenomic testing (PGT).

OBJECTIVE

To evaluate the impact of real-world cardiovascular (CV)-related PGT on clinical outcomes, healthcare resource utilisation (HCRU) and cost in a large, heterogeneous population.

METHODS

Individuals with Medicare Advantage Prescription Drug, Medicaid, or commercial coverage between 1/1/2011 and 9/30/2015 and ≥1 atherosclerotic CV-related diagnosis were identified. Those with ≥1 claim for CV-related PGT were included in the test group (index date = 1st PGT claim) and matched 1:2 to controls without PGT. Individuals aged <22 or ≥90 years old on the index date, with <12 months continuous enrollment before and after the index date, or without an ASCVD-related diagnosis in the 12-month pre-index period were excluded. The primary outcome was occurrence of a major CV event during the 12-month post-index period.

RESULTS

After adjustment, the PGT group was significantly more likely to experience ischaemic stroke, pulmonary embolism, deep vein thrombosis or a composite event compared with controls. Adjusting for baseline characteristics, HCRU was significantly higher for the test group across all measured outcomes except all-cause and ASCVD-related inpatient admissions. Median all-cause and ASCVD-related healthcare costs were significantly higher for the test group.

CONCLUSIONS

Real world PGT in a large population did not improve outcomes. Tailoring medication therapy to each patient holds great promise for providing quality care but a deeper understanding of how widespread utilisation of PGT might impact objective health outcomes is needed.

Study of the Association of PEAR1, P2Y12, and UGT2A1 Polymorphisms with Platelet Reactivity in Response to Dual Antiplatelet Therapy in Chinese Patients

Objectives: Genetic variation is thought to contribute to considerable interindividual variability in platelet function, and there is a pressing need to identify genetic markers that can be used to predict the response to treatment. Our study investigated whether PEAR1, P2Y12, and UGT2A1 polymorphisms were associated with platelet reactivity in response to dual antiplatelet therapy in Chinese patients with acute coronary syndrome. Methods: Patients with inhibition of platelet aggregation (IPA) < 30% after treatment were classified as the high platelet reactivity (HPR) group. Patients with IPA > 30% were classified as the normal platelet reactivity (NPR) group. ADP-induced platelet aggregation was measured by thromboelastography (TEG) platelet-mapping assay. Thirteen single nucleotide polymorphisms (SNPs) of PEAR1, P2Y12 and UGT2A1 were genotyped using the Mass­ARRAY platform. Results: Seven SNPs were significantly associated with ADP-induced platelet aggregation by univariate analysis. Major allele G at rs12041331, minor allele G at rs2644592, minor allele C at rs11264580, and minor allele C at rs11249454 were significantly associated with HPR, whereas minor allele T at rs57731889, minor allele A at rs16863356, and minor allele T at rs7634096 were significantly associated with NPR. The mean IPA was significantly lower in patients suffering recurrent ischemic events than in patients without recurrent events in our study (p = 0.048). Conclusions: Our findings suggest that PEAR1, P2Y12, and UGT2A1 genetic variants may be potential biomarkers that can be used to guide clinical applications of clopidogrel and aspirin in Chinese patients.

Prevention of minor myocardial injury after elective percutaneous coronary intervention: comparison of ticagrelor versus clopidogrel

BACKGROUND

Elective percutaneous coronary intervention (ePCI) may cause minor elevation of cardiac enzymes, so-called minor myocardial injury (MMI) which can be due to different pathophysiological mechanism (e.g. distal embolisation, side branch occlusion, increased platelet activation triggered by the intracoronary metallic stents). We aimed to compare the effectiveness of ticagrelor versus clopidogrel for the prevention of MMI and major adverse clinical events (MACEs) after ePCI.

METHODS

Study population consisted of two groups of patients based on the treatment: Group I, receiving clopidogrel (n = 104), Group II, receiving ticagrelor (n = 96). Cardiac troponin I (cTnI), CK-MB were studied before and 12 hours after the procedure. Elevation of cTnI greater than 0.06 ng/ml was considered as MMI. All patients were also evaluated for the MACEs (death, myocardial infarction, stroke and transient ischaemic attack).

RESULTS

Fifty-two of 200 patients (26%) had MMI after the procedure. The minor myocardial injury was significantly more prevalent in clopidogrel group than that of ticagrelor group (33% vs. 19%, p = .03). Myocardial infarction (MI) and MACEs were significantly higher in the clopidogrel group (15% vs. 6%, for MI, p = .04; 16% vs. 6%, for MACEs, p = .03, respectively). Multivariate analysis demonstrated antiplatelet treatment, saphenous graft intervention, type-C lesion as independent predictors of MMI.

CONCLUSIONS

Present study showed that the combination of ticagrelor and aspirin was more effective than combination of clopidogrel and aspirin in decreasing MMI and MACEs after elective stenting.

A synergic effect between CYP2C19*2, CYP2C19*3 loss-of-function and CYP2C19*17 gain-of-function alleles is associated with Clopidogrel resistance among Moroccan Acute Coronary Syndromes patients

Objective

The main objective of our study was to investigate the association of CYP2C19*2 and CYP2C19*3 loss-of-function and CYP2C19*17 gain-of-function variants of CYP2C19 gene with Clopidogrel resistance in a sample of Moroccan Acute Coronary Syndromes patients.

Results

Our results showed the existence of a synergic effect between the three alleles, statistically very significant, on Clopidogrel resistance among the treated patients (P = 0.0033). For the three variants of the CYP2C19 gene, the heterozygous and homozygous mutant genotypes were the most frequent among ACS patients (CYP2C19*2: 82.76% GA and 10.35% AA; CYP2C19*3: 76.67% GA and 18.33% AA; CYP2C19*17: 66.67% CT and 18.66% TT). Allelic frequencies were 51.73% vs 48.27% (P < 0.001); 56.67% vs 43.33% (P < 0.001); and 52% vs 48% (P = 0.01) for the mutant and wild type alleles of the CYP2C19*2, CYP2C19*3 and CYP2C19*17 variants respectively. Our results support a role of CYP2C19 gene variants as a potential marker of Clopidogrel response. Understanding the functional and clinical consequences of these variants may help for treating patients more effectively, they could be genetically screened and appropriate dose adjustments could be made on the basis of their CYP2C19 genotype.

Electronic supplementary material

The online version of this article (10.1186/s13104-018-3132-0) contains supplementary material, which is available to authorized users.

Genomewide Association Study Identifies Novel Genetic Loci That Modify Antiplatelet Effects and Pharmacokinetics of Clopidogrel

Genetic variants in the pharmacokinetic (PK) mechanism are the main underlying factors affecting the antiplatelet response to clopidogrel. Using a genomewide association study (GWAS) to identify new genetic loci that modify antiplatelet effects in Chinese patients with coronary heart disease, we identified novel variants in two transporter genes (SLC14A2 rs12456693, ATP‐binding cassette [ABC]A1 rs2487032) and in N6AMT1 (rs2254638) associated with P2Y12 reaction unit (PRU) and plasma active metabolite (H4) concentration. These new variants dramatically improved the predictability of PRU variability to 37.7%. The associations between these loci and PK parameters of clopidogrel and H4 were observed in additional patients, and its function on the activation of clopidogrel was validated in liver S9 fractions (P < 0.05). Rs2254638 was further identified to exert a marginal risk effect for major adverse cardiac events in an independent cohort. In conclusion, new genetic variants were systematically identified as risk factors for the reduced efficacy of clopidogrel treatment.

Associations of CYP3A4, NR1I2, CYP2C19 and P2RY12 polymorphisms with clopidogrel resistance in Chinese patients with ischemic stroke

AIM

There is a high incidence of the antiplatelet drug clopidogrel resistance (CR) in Asian populations. Because clopidogrel is a prodrug, polymorphisms of genes encoding the enzymes involved in its biotransformation may be the primary influential factors. The goal of this study was to investigate the associations of polymorphisms of CYP3A4, NR1I2, CYP2C19 and P2RY12 genes with CR in Chinese patients with ischemic stroke.

METHODS

A total of 191 patients with ischemic stroke were enrolled. The patients were treated with clopidogrel for at least 5 days. Platelet function was measured by light transmission aggregometry. The SNPs NR1I2 (rs13059232), CYP3A4(*)1G (rs2242480), CYP2C19(*)2 (rs4244285) and P2RY12 (rs2046934) were genotyped.

RESULTS

The CR rate in this population was 36%. The CYP2C19(*)2 variant was a risk factor for CR ((*)2/(*)2+wt/(*)2 vs wt/wt, OR: 2.366, 95% CI: 1.180-4.741, P=0.014), whereas the CYP3A4(*)1G variant had a protective effect on CR ((*)1/(*)1 vs (*)1G/(*)1G+(*)1/(*)1G, OR: 2.360, 95% CI: 1.247-4.468, P=0.008). The NR1I2 (rs13059232) polymorphism was moderately associated with CR (CC vs TT+TC, OR: 0.533, 95% CI: 0.286-0.991, P=0.046). The C allele in P2RY12 (rs2046934) was predicted to be a protective factor for CR (CC+TC vs

TT, OR

0.407, 95% CI: 0.191-0.867, P=0.018). In addition, an association was found between hypertension and CR (P=0.022).

CONCLUSION

The individuals with both the CYP2C19(*)2 allele and hypertension are at high risk of CR during anti-thrombosis therapy. The CYP3A4(*)1G allele, P2RY12 (rs2046934) C allele and NR1I2 (rs13059232) CC genotype may be protective factors for CR. The associated SNPs studied may be useful to predict clopidogrel resistance in Chinese patients with ischemic stroke.

CYP2C19*2 and Other Allelic Variants Affecting Platelet Response to Clopidogrel Tested by Thrombelastography in Patients with Acute Coronary Syndrome

Background:

To investigate the contributions of CYP2C19 polymorphisms to the various clopidogrel responses tested by thrombelastography (TEG) in Chinese patients with the acute coronary syndrome (ACS).

Methods:

Patients were screened prospectively with ACS diagnose and were treated with clopidogrel and aspirin dual antiplatelet therapy. CYP2C19 loss of function (LOF) and gain of function (GOF) genotype, adenosine 5′-diphosphate (ADP)-channel platelet inhibition rate (PIR) tested by TEG and the occurrence of 3-month major adverse cardiovascular events and ischemic events were assessed in 116 patients.

Results:

High on-treatment platelet reactivity (HTPR) prevalence defined by PIR <30% by TEG in ADP-channel was 32.76% (38/116). With respect to the normal wild type, CYP2C19*2, and *3 LOF alleles, and *17 GOF alleles, patients were classified into three metabolism phenotypes: 41.38% were extensive metabolizers (EMs), 56.90% were intermediate metabolizers (IMs), and 1.72% were poor metabolizers (PMs). Of the enrolled patients, 31.47%, 5.17%, and 0.43%, respectively, were carriers of *2, *3, and *17 alleles. The HTPR incidence differed significantly according to CYP2C19 genotypes, accounting for 18.75%, 41.54%, and 100.00% in EMs, IMs, and PMs, respectively. Eighteen (17.24%) ischemic events occurred during the 3-month follow-up, and there was a significant difference in ischemic events between HTPR group and nonhigh on-treatment platelet reactivity group.

Conclusions:

Genetic CYP2C19 polymorphisms are relative to the inferior, the antiplatelet activity after clopidogrel admission and may increase the incidence of ischemic events in patients with ACS.

Development of a physiology-directed population pharmacokinetic and pharmacodynamic model for characterizing the impact of genetic and demographic factors on clopidogrel response in healthy adults

Clopidogrel (Plavix®), is a widely used antiplatelet agent, which shows high inter-individual variability in treatment response in patients following the standard dosing regimen. In this study, a physiology-directed population pharmacokinetic/pharmacodynamic (PK/PD) model was developed based on clopidogrel and clopidogrel active metabolite (clop-AM) data from the PAPI and the PGXB2B studies using a step-wise approach in NONMEM (version 7.2). The developed model characterized the in vivo disposition of clopidogrel, its bioactivation into clop-AM in the liver and subsequent platelet aggregation inhibition in the systemic circulation reasonably well. It further allowed the identification of covariates that significantly impact clopidogrel's dose-concentration-response relationship. In particular, CYP2C19 intermediate and poor metabolizers converted 26.2% and 39.5% less clopidogrel to clop-AM, respectively, compared to extensive metabolizers. In addition, CES1 G143E mutation carriers have a reduced CES1 activity (82.9%) compared to wild-type subjects, which results in a significant increase in clop-AM formation. An increase in BMI was found to significantly decrease clopidogrel's bioactivation, whereas increased age was associated with increased platelet reactivity. Our PK/PD model analysis suggests that, in order to optimize clopidogrel dosing on a patient-by-patient basis, all of these factors have to be considered simultaneously, e.g. by using quantitative clinical pharmacology tools.

Determination of genotypes using a fully automated molecular detection system

CONTEXT

Although the value of pharmacogenomics to improve patient outcomes has become increasingly clear, adoption in medical practice has been slow, which can be attributed to several factors, including complicated and expensive testing procedures and required equipment, lack of training by private practice physicians, and reluctance of both private and commercial payers to reimburse for such testing.

OBJECTIVES

To evaluate a fully automated molecular detection system for human genotyping assays, starting with anticoagulated whole blood samples, and to perform all sample preparation, assay, and analysis steps automatically with actionable results reported by the system's software.

DESIGN

The genotypes of 254 random individuals were determined by performing bidirectional DNA sequencing, and that information was used to statistically train the imaging software of the automated molecular detection system to distinguish the 3 possible genotypes (ie, homozygous wild type, heterozygous, and homozygous mutant) at each of 3 different loci (CYP2C9*2, CYP2C9*3, and VKORC1).

RESULTS

The resulting software algorithm was able to correctly identify the genotypes of all 254 individuals (100%) evaluated without any further user analysis.

CONCLUSIONS

The EncompassMDx workstation (Rheonix, Inc, Ithaca, New York) is a molecular detection system that can automatically determine the genotypes of individuals in an unattended manner. Considerably less technical expertise was required to achieve results identical to those obtained using more complex, time-consuming, and expensive bidirectional DNA sequencing. This optimized system may dramatically simplify and reduce the costs of pharmacogenomics testing, thus leading to more-widespread use.

Clinical pharmacokinetics and pharmacodynamics of clopidogrel

Acute coronary syndromes (ACS) remain life-threatening disorders, which are associated with high morbidity and mortality. Dual antiplatelet therapy with aspirin and clopidogrel has been shown to reduce cardiovascular events in patients with ACS. However, there is substantial inter-individual variability in the response to clopidogrel treatment, in addition to prolonged recovery of platelet reactivity as a result of irreversible binding to P2Y12 receptors. This high inter-individual variability in treatment response has primarily been associated with genetic polymorphisms in the genes encoding for cytochrome (CYP) 2C19, which affect the pharmacokinetics of clopidogrel. While the US Food and Drug Administration has issued a boxed warning for CYP2C19 poor metabolizers because of potentially reduced efficacy in these patients, results from multivariate analyses suggest that additional factors, including age, sex, obesity, concurrent diseases and drug-drug interactions, may all contribute to the overall between-subject variability in treatment response. However, the extent to which each of these factors contributes to the overall variability, and how they are interrelated, is currently unclear. The objective of this review article is to provide a comprehensive update on the different factors that influence the pharmacokinetics and pharmacodynamics of clopidogrel and how they mechanistically contribute to inter-individual differences in the response to clopidogrel treatment.

Implementation of pharmacogenetics: the University of Maryland Personalized Anti-platelet Pharmacogenetics Program

Despite a substantial evidence base, implementation of pharmacogenetics into routine patient care has been slow due to a number of non-trivial practical barriers. We implemented a Personalized Anti-platelet Pharmacogenetics Program (PAP3) for cardiac catheterization patients at the University of Maryland Medical Center and the Baltimore Veterans Administration Medical Center Patients' are offered CYP2C19 genetic testing, which is performed in our Clinical Laboratory Improvement Amendment (CLIA)-certified Translational Genomics Laboratory. Results are returned within 5 hr along with clinical decision support that includes interpretation of results and prescribing recommendations for anti-platelet therapy based on the Clinical Pharmacogenetics Implementation Consortium guidelines. Now with a working template for PAP3, implementation of other drug-gene pairs is in process. Lessons learned as described in this article may prove useful to other medical centers as they implement pharmacogenetics into patient care, a critical step in the pathway to personalized and genomic medicine.

Comparison of delivery strategies for pharmacogenetic testing services

The number and use of pharmacogenetic tests to assess a patient's likelihood of response or risk of an adverse event is expanding across medical specialties and becoming more prevalent. During this period of development and translation, different approaches are being investigated to optimize delivery of pharmacogenetic services. In this paper, we review pre-emptive and point-of-care delivery approaches currently implemented or being investigated and discuss the advantages and disadvantages of each approach. The continued growth in knowledge about the genetic basis of drug response combined with development of new and less expensive testing technologies and electronic medical records will impact future delivery systems. Regardless of delivery approach, the currently limited knowledge of health professionals about genetics generally or PGx specifically will remain a major obstacle to utilization.