Cost-effectiveness analysis of CYP2C19 genotype-guided antiplatelet therapy for patients with acute minor ischemic stroke and high-risk transient ischemic attack in China

AIMS

The study aimed to estimate the cost-effectiveness of CYP2C19 genotype-guided antiplatelet therapy using cilostazol and ticagrelor as an alternative to clopidogrel, compared to conventional antiplatelet therapy with clopidogrel and aspirin.

METHODS

A 90-day decision tree and 30-year Markov model were employed to assess the costs and quality-adjusted life years (QALYs) of personalized antiplatelet therapy for patients with minor ischemic stroke and high-risk transient ischemic attack, compared to conventional antiplatelet therapy in the Chinese healthcare system. The primary outcome was the incremental cost-effectiveness ratio (ICER). The data sources included clinical trials, published literature, official documents and local prices. One-way sensitivity analysis and probabilistic sensitivity analysis were performed to confirm the robustness of the findings.

RESULTS

The base-case analysis indicated that the CYP2C19 genotype-guided antiplatelet strategy was cost-effective, and cilostazol group and ticagrelor group yielded an ICER of 3327.40 US dollars (USD)/QALY and 3426.92 USD/QALY, respectively, which were less than threshold. The one-way sensitivity analysis showed the results were robust, where the most sensitive parameter was the disability distribution in the modified Rankin scale 3-5. The probabilistic analysis showed that the CYP2C19 genotype-guided antiplatelet therapy with either cilostazol or ticagrelor was 100% cost-effective under the willingness-to-pay threshold.

CONCLUSIONS

CYP2C19 genotype-guided antiplatelet therapy using cilostazol and ticagrelor as an alternative to clopidogrel appeared to be more cost-effective than conventional antiplatelet therapy for acute minor ischemic stroke and high-risk transient ischemic attack patients over 30 years in China.

Association between CYP2C19*2/*3 Polymorphisms and Coronary Heart Disease

This study sought to explore the relationship between cytochrome P450 2C19 (CYP2C19) *2/*3 polymorphisms and the development of coronary heart disease (CHD), and to evaluate the influence of the single nucleotide polymorphisms (SNPs) on the occurrence of adverse clinical events in CHD patients. A total of 231 consecutive patients candidate for percutaneous coronary intervention genotyped for CYP2C19*2 (681G>A) and *3 (636G>A) polymorphisms were enrolled. The adverse clinical events were recorded during a follow-up period of 14 months. The incidence of CHD, according to coronary angiography, was significantly higher (P=0.025) in CYP2C19*2 carriers group. Stepwise binary logistic regression analysis revealed that among factors that potentially influenced the presence of CHD (age>60 years, gender, BMI, etc.), CYP2C19*2 carriers (OR 1.94, 95% CI: 1.08-3.50, P=0.028) and male gender (OR 2.74, 95% CI: 1.58-4.76, P=0.001) were independent predictors, which were associated with the presence of CHD. The follow-up results showed that the incidence of adverse cardiovascular events within 14 months of discharge was significantly higher in the CYP2C19*2 carriers than in the non-carriers (21.6% vs. 6.3%, P=0.019). The results of the multivariate Cox proportional hazards model showed that CYP2C19*2 loss-of-function was the only independent factor which predicted the coronary events during the follow-up period of 14 months (OR=3.65, 95% CI 1.09-12.25, P=0.036). The adverse impact of CYP2C19*2 polymorphisms was found not only in the risk of the presence of CHD, but also in the adverse cardiovascular events in CHD patients during the follow-up period of 14 months. However the same influence was not found in CYP2C19*3 mutation in Chinese Han population.

The Pharmacokinetics and Pharmacodynamics of Prasugrel and Clopidogrel in Healthy Japanese Volunteers

The dosing regimen of prasugrel adjusted for Japanese patients was compared with that of clopidogrel by analyzing the pharmacokinetics and pharmacodynamics in 40 healthy Japanese subjects in a randomized, single‐blind crossover study. In period 1, the subjects received either 300 mg clopidogrel or 20 mg prasugrel; after a >2‐week interval (period 2), the drug was switched. Blood samples of 36 of the 40 subjects were collected for analysis of pharmacokinetics, pharmacodynamics, and CYP2C19 genotypes. The plasma concentration of the active metabolite of prasugrel increased rapidly and reached its peak 30 minutes postadministration, whereas that of the active metabolite of clopidogrel reached its peak 1 hour postadministration. The mean AUC and C_max of the active metabolite of clopidogrel, but not those of prasugrel, were CYP2C19 genotype dependent. Prasugrel rapidly inhibited platelet aggregation, reaching its maximum effect 1 hour postadministration. Clopidogrel, on the other hand, showed maximum inhibition 2 hours postadministration. Platelet aggregation inhibition by clopidogrel was significantly lower in the poor‐metabolizer subjects than in the extensive‐metabolizer subjects. Overall, prasugrel inhibited platelet aggregation more rapidly and more effectively in healthy Japanese subjects than was observed for clopidogrel.

Rapid metabolizer genotype of CYP2C19 is a risk factor of being refractory to proton pump inhibitor therapy for reflux esophagitis

BACKGROUND

Proton pump inhibitors (PPIs) are mainly metabolized by cytochrome P450 2C19 (CYP2C19) and used as the first-line therapy for gastroesophageal reflux disease (GERD). However, while several studies have examined the influence of CYP2C19 polymorphism on GERD treatment with PPIs, most have had small sample sizes and were conducted in a single center. Here, we used meta-analysis to investigate whether or not the CYP2C19 rapid metabolizer (RM) genotype is a risk factor for GERD patients being refractory to PPI therapy.

METHODS

PubMed and other electronic databases were systematically searched up to August 2014 using the following terms: "GERD and CYP2C19", "esophagitis and CYP2C19", and "non-erosive reflux disease and CYP2C19." Searches were limited to publications in English, and two investigators evaluated eligible studies and extracted data.

RESULTS

The total efficacy rate of PPIs for GERD, including reflux esophagitis (RE) and non-erosive reflux disease, was 56.4% (95% confidence interval [CI]; 53.9-58.9%, 870/1543) in intention-to-treat analysis and 63.8% (95%CI; 61.3-66.2%, 950/1489) in per-protocol analysis. Efficacy rates varied significantly between CYP2C19 genotypes (intention-to-treat analysis: RMs, 52.2% [315/604]; intermediate metabolizers, 56.7% [298/526]; poor metabolizers [PMs], 61.3% [138/225]; P = 0.047). Among RE patients, CYP2C19 RMs had an increased risk of being refractory to PPI therapy compared with PMs (odds ratio: 1.661, 95% CI: 1.023-2.659, P = 0.040).

CONCLUSIONS

The present meta-analysis demonstrates that CYP2C19 RMs with RE have an increased risk of being refractory to PPI therapy compared with PMs. Individualized dosing regimen with PPIs based on CYP2C19 genotype might be a valid therapeutic strategy for overcoming insufficient gastric acid inhibition.

Protocol for the comparison of triflusal and clopidogrel in secondary prevention of stroke based on cytochrome P450 2C19 genotyping (MASETRO study): A multicenter, randomized, open-label, parallel-group trial

RATIONALE AND AIM

The antiplatelet effect of clopidogrel is reportedly influenced by cytochrome P450 2C19 (CYP2C19) polymorphisms. However, there is no data concerning the relationship between stroke recurrence and CYP2C19 polymorphisms in patients treated with clopidogrel for secondary prevention of ischemic stroke. Triflusal may be an alternative therapy for clopidogrel in patients with poor genotype. The Comparison of Triflusal and Clopidogrel Effects in Secondary Prevention of Stroke Based on Cytochrome P450 2C19 Genotyping (MAESTRO) study will investigate the effect of antiplatelet agents based on CYP2C19 polymorphisms in secondary prevention of ischemic stroke.

SAMPLE SIZE AND DESIGN

Assuming that 55% of patients belong to the poor genotype group, the required sample size is 1080 patients with at least 24 months of follow-up. This study is designed as a prospective, multicenter, randomized, parallel-group, open-label, and blind genotype trial. Patients who experience their first non-cardiogenic ischemic stroke within 30 days prior to screening are eligible. Patients received 300 mg triflusal twice a day or 75 mg clopidogrel once daily during the trial. The study is registered with ClinicalTrials.gov (NCT01174693).

STUDY OUTCOME

The primary outcome is recurrent ischemic stroke or hemorrhagic stroke. Secondary outcomes consist of composite major vascular events including stroke, myocardial infarction, coronary revascularization, or vascular death.

DISCUSSION

Personalized medicine may be essential for patients according to individual drug metabolism abilities. MAESTRO is the first prospective study designed to evaluate the effect of CYP2C19 polymorphism in secondary stroke prevention and will resolve several questions regarding preventive antiplatelet agents for recurrent stroke.

Effect of bacterial and host factors on Helicobacter pylori eradication therapy

INTRODUCTION

A clearer understanding of the factors affecting the cure rate of Helicobacter pylori infection might lead to the development of novel prevention strategies and therapeutic targets.

AREAS COVERED

This review covers two important issues that affect the eradication of H. pylori: bacterial and host factors. Several virulence factors have been shown to be predictors for gastroduodenal diseases. Successful treatment of H. pylori infection also depends on host genetic factors such as CYP2C19 and IL-1B. The latest evidence on host genetic factors is discussed.

EXPERT OPINION

The authors identify three main targets for achieving effective eradication therapy. The first therapeutic target is to identify counter measures for antibiotic-resistant H. pylori strains. Thus, antibiotic susceptibility should be checked in all patients, ideally, before the start of eradication treatment. The second therapeutic target is the inhibition of acid suppression. Maintaining a high intragastric pH for 24 h increases the effectiveness of some antibiotics and the eradication effects for H. pylori. The third therapeutic target is to identify high-risk groups; the CYP2C19 and IL-1B polymorphisms are candidates for significant risk factors. A personalized medical approach will likely increase the cure rate of H. pylori infection.

Analysis of compound heterozygous CYP2C19 genotypes to determine cis and trans configurations

BACKGROUND

Through allele specific PCR we studied 220 CYP2C19 compound heterozygous samples, of unknown ethnicity, to determine the haplotype for each of the variations within a sample.

MATERIALS & METHODS

The genotypes assessed were: 180 *2 and *17 samples (100% in trans); 20 *2 and *11 samples (100% in cis); ten *4 and *17 samples (50% of the samples were *1/*4B and 50% *4A/*17); six *2, *11 and *17 samples (100% showed *2 and *11 in cis, and *17 in trans); two *2, *4 and *17 samples (100% *4B with *2 in trans); one sample with *17 and *34 (these were in trans); and one sample that contained *2, *17, c.463G>T (p.E155X; *17 and c.463G>T were in cis, with *2 in trans).

RESULTS & CONCLUSION

In our study, we observed a different frequency for the *4B allele (when a sample contains both *4 and *17); and identified *17 occurring in cis with a novel nonsense allele. Accurately assessing a patient's genotype, including assignment of a haplotype, can be important when making a phenotype prediction.

Computer-aided identification of novel protein targets of bisphenol A

The xenoestrogen bisphenol A (2,2-bis-(p-hydroxyphenyl)-2-propane, BPA) is a known endocrine-disrupting chemical used in the fabrication of plastics, resins and flame retardants, that can be found throughout the environment and in numerous every day products. Human exposure to this chemical is extensive and generally occurs via oral route because it leaches from the food and beverage containers that contain it. Although most of the effects related to BPA exposure have been linked to the activation of the estrogen receptor (ER), the mechanisms of the interaction of BPA with protein targets different from ER are still unknown. Therefore, the objective of this work was to use a bioinformatics approach to identify possible new targets for BPA. Docking studies were performed between the optimized structure of BPA and 271 proteins related to different biochemical processes, as selected by text-mining. Refinement docking experiments and conformational analyses were carried out using LigandScout 3.0 for the proteins selected through the affinity ranking (lower than -8.0kcal/mol). Several proteins including ERR gamma (-9.9kcal/mol), and dual specificity protein kinases CLK-4 (-9.5kcal/mol), CLK-1 (-9.1kcal/mol) and CLK-2 (-9.0kcal/mol) presented great in silico binding affinities for BPA. The interactions between those proteins and BPA were mostly hydrophobic with the presence of some hydrogen bonds formed by leucine and asparagine residues. Therefore, this study suggests that this endocrine disruptor may have other targets different from the ER.