Clopidogrel: a pharmacoeconomic review of its use in patients with non-ST elevation acute coronary syndromes

Clustering of ABCB1 and CYP2C19 Genetic Variants Predicts Risk of Major Bleeding and Thrombotic Events in Elderly Patients with Acute Coronary Syndrome Receiving Dual Antiplatelet Therapy with Aspirin and Clopidogrel

OBJECTIVE

The clinical efficacy of clopidogrel in secondary prevention of vascular events is hampered by marked inter-patient variability in drug response, which partially depends on genetic make-up. The aim of this pilot prospective study was to evaluate 12-month cardiovascular outcomes in elderly patients with acute coronary syndrome (ACS) receiving dual antiplatelet therapy (aspirin and clopidogrel) according to the clustering of CYP2C19 and ABCB1 genetic variants.

METHODS

Participants were 100 consecutive ACS patients who were genotyped for CYP2C19 (G681A and C-806T) and ABCB1 (C3435T) polymorphisms, which affect clopidogrel metabolism and bioavailability, using PCR-restriction fragment length polymorphism. They were then grouped as poor, extensive and ultra-rapid metabolisers based on the combination of CYP2C19 loss-of-function (CYP2C19*2) and gain-of-function (CYP2C19*17) alleles and ABCB1 alleles. The predictive value of each phenotype for acute vascular events was estimated based on 12-month cardiovascular outcomes.

RESULTS

The poor metabolisers were at an increased risk of thrombotic events (OR 1.26; 95% CI 1.099-1.45; χ2 = 5.676; p = 0.027), whereas the ultra-rapid metabolisers had a 1.31-fold increased risk of bleeding events compared with the poor and extensive metabolisers (OR 1.31; 95% CI 1.033-1.67; χ2 = 5.676; p = 0.048). Logistic regression model, including age, sex, BMI and smoking habit, confirmed the differential risk of major events in low and ultra-rapid metabolisers.

CONCLUSIONS

Our findings suggest that ACS patients classified as 'poor or ultra-rapid' metabolisers based on CYP2C19 and ABCB1 genotypes should receive alternative antiplatelet therapies to clopidogrel.

Economic evaluation of clopidogrel in acute coronary syndrome patients without ST-segment elevation in Greece: a cost-utility analysis

BACKGROUND

Current guidelines recommend treatment with antiplatelet and anticoagulant therapy for the secondary prevention of atherothrombotic events among patients with non-ST-segment elevation myocardial infarction (NSTEMI) or unstable angina (UA). The CURE (Clopidogrel in Unstable angina to prevent Recurrent Events) trial has shown that clopidogrel alone or in combination with aspirin is more effective in reducing the risk of atherothrombotic events than aspirin alone in NSTEMI or UA patients. However, in the current climate of financial constraints, the effectiveness of a treatment should be considered in conjunction with its long-term economic costs to determine the best possible care.

OBJECTIVE

To evaluate the cost effectiveness of 1 year of treatment with clopidogrel in addition to aspirin in NSTEMI or UA patients from the third-party-payer perspective in Greece.

METHODS

An existing Markov model consisting of six states (NSTEMI/UA/no event, first year with stroke, history of stroke, first year with myocardial infarction [MI], history of MI and death) was adapted and extended to the Greek healthcare setting for year 2012. Utility values obtained from a Greek national study were assigned to each health state in order to estimate the quality-adjusted life-years (QALYs). Costs assigned to each health state included antiplatelet treatment cost, cost for the management of adverse events and the costs for concomitant medication, hospitalization, outpatient visits, rehabilitation and nursing. Cost effectiveness and cost utility was expressed as the cost per life-year (LY) gained and QALY gained, respectively. A probabilistic sensitivity analysis was conducted.

RESULTS

The Markov analysis predicts a discounted survival of 8.27 years in the aspirin treatment group and 8.41 years in the aspirin plus clopidogrel treatment group. The corresponding discounted QALYs were 6.88 and 7.00, respectively. The cumulated lifetime costs per patient were € 18 779 and € 19 191, for the aspirin and aspirin plus clopidogrel treatment arms, respectively. The incremental cost-effectiveness ratio (ICER) with the addition of clopidogrel was &U20AC;2951 for each LY saved and &U20AC;3541 for each QALY saved. Finally, clopidogrel plus aspirin was found to be cost effective in more than 95% of simulated samples at a threshold of &U20AC;7000 per discounted QALY gained.

CONCLUSION

One-year treatment with clopidogrel in addition to aspirin is a cost-effective treatment option for secondary prevention in patients with acute coronary syndrome without ST-segment elevation in Greece.

Economic evaluation of BDP/formoterol fixed vs two single inhalers in asthma treatment

BACKGROUND

Asthma treatment costs are substantial, the largest proportion being incurred by medications. Combination therapy with inhaled corticosteroids (ICS) and long-acting beta(2)-agonists (LABA) is recommended in patients not adequately controlled by ICS alone. Aim of this study was to compare costs and health outcomes of a fixed ICS-LABA combination of beclomethasone dipropionate (BDP) and formoterol fumarate (FF) vs the same drugs delivered via separate inhalers in Germany.

METHODS

A cost-minimization analysis, a cost-effectiveness analysis, as well as a threshold analysis were undertaken. Efficacy results were obtained from a recent clinical trial. Cost inputs include medical costs, physician costs, and hospital admission costs. Medical costs, health outcomes, and treatment costs were also varied to assess their impact on results.

RESULTS

Beclomethasone dipropionate/FF fixed combination was less costly compared to BDP + FF delivered as separate inhalers, costs totaling euro 525 and euro 637, respectively, over a 24-week treatment period. The incremental cost-effectiveness ratio was euro-9.77 per additional day free of asthma symptoms. Equal cost-effectiveness ratios would still be obtained at a price of the fixed combination increased by 3.4-fold.

CONCLUSION

A cost-minimization analysis as well as a cost-effectiveness analysis for Germany based on different product price calculations show that BDP/FF fixed combination is superior to BDP + FF delivered via separate inhalers.

Revaluation of clopidogrel: let the data speak for themselves

Clopidogrel was believed to be superior to aspirin by the well-known CAPRIE trial. However, no other large clinical trials demonstrated the same results, but all focused on the combination use of clopidogrel with aspirin, and combination therapy in CREDO was called the "Emperor's New Clothes". However, no one overturned the results of these clinical trials by quantitatively analyzing them. We reviewed ten large-scale clinical trials about clopidogrel. On the basis of results of CAPRIE, CREDO and CHARISMA trials, we re-estimated their minimal sample sizes and their powers by three well-established statistical methodologies. From the results of CAPRIE, we inferred that the minimal sample size should be 85 086 or 84 968 but its power was only 30.70%. A huge gap existed. The same was also true of CREDO and CHARISMA trials. Moreover, in CAPRIE trial, 0 was included in the 95% confidence interval and 1 was included in the 95% confidence interval for the relative risk. There were some paradoxical data in CAPRIE trial. We are led to conclude that the results in CAPRIE, CREDO, and from the subgroup analysis in CHARISMA trials were questionable. These results failed to demonstrate that clopidogrel was superior to aspirin or that clopidogrel used in combination with aspirin was better than aspirin alone. The cost-effectiveness analyses by some previous studies were not reliable.

Evaluation of hospitalization and follow-up care costs among patients hospitalized with ACS treated with a stent and clopidogrel

OBJECTIVE

This retrospective claims study was performed to evaluate the initial and subsequent healthcare costs in patients with acute coronary syndrome (ACS) who had been treated with stent placement and clopidogrel following discharge from the hospital.

METHOD AND RESULTS

This was a retrospective, administrative claims-based analysis from a large, geographically diverse US managed care plan affiliated with i3 Innovus. Study subjects were commercially insured enrollees, aged > or = 18, who were hospitalized for ACS between 1 January 2000 and 31 December 2004 with a stent placed, and had at least one filled prescription for clopidogrel within 7 days of discharge from the index hospitalization. Of the 9135 subjects included in the cost analysis, 2241 subjects experienced a subsequent event. On average, subjects with a second event incurred $32,495 more in medical costs over 2 years and $39,742 more in medical costs over 3 years versus those who did not have a second event. Excluding ischemic hospitalizations, subjects with a second event incurred $7257 and $9724 more in medical costs than patients without a second event during the 2 and 3 years following discharge from the index hospitalization, respectively.

CONCLUSIONS

Significant cost increases were observed among patients who had a subsequent hospitalization for an ischemic event compared to those without a subsequent hospitalization. Cost increases were still present after excluding costs of the ischemic hospitalizations. The findings of this study must be considered within the limitations of database analysis as claims data are collected for the purpose of payment and not research.

Cost effectiveness of fondaparinux in non-ST-elevation acute coronary syndrome

BACKGROUND

Fondaparinux has been shown to reduce the risk of major bleeding and 30-day mortality compared with enoxaparin, in patients with non-ST-elevation acute coronary syndrome (NSTE-ACS). However, its cost effectiveness is not well known.

OBJECTIVE

To evaluate the effectiveness and economic attractiveness of fondaparinux relative to enoxaparin in patients with NSTE-ACS treated with triple antiplatelet therapy and early (non-urgent) invasive strategy.

METHODS

The decision model compares two alternative strategies: subcutaneous (SC) enoxaparin (1 mg/kg 12 hourly) versus SC fondaparinux (2.5 mg/day) in NSTE-ACS patients pre-treated with triple antiplatelet therapy and early revascularization. Cost-effectiveness and cost-utility analyses were performed from a healthcare perspective, based on a Markov model with a time horizon of the patient lifespan. Univariate sensitivity analysis and probabilistic (Monte Carlo) microsimulation analysis were performed.

RESULTS

In the base-case analysis (65 years, Thrombolysis In Myocardial Infarction [TIMI] score 4), the use of fondaparinux was associated with a significant reduction in major bleeding, a slight reduction in adverse cardiac events, and minor improvements in survival and QALYs, together with a small reduction in costs. The dominance of fondaparinux over enoxaparin remained unchanged in the univariate sensitivity analyses. According to Monte Carlo simulation, fondaparinux was cost saving in 99.9% of cases.

CONCLUSION

Compared with enoxaparin, the use of fondaparinux in patients with NSTE-ACS managed with an early invasive strategy appears to be cost effective, even in patients with a low risk of bleeding.

Pharmacoeconomic concepts in antiplatelet therapy: understanding cost-effectiveness analyses using clopidogrel as an example

The rising cost of drug therapy has been accompanied by demands from payers for pharmacoeconomic studies to assess the value for money of new treatments. There are 5 types of such analyses: cost analysis (evaluates only costs); cost minimization (compares costs of treatments with identical outcomes); cost-effectiveness (evaluates the cost of treatment in relation to clinical benefit to derive a cost per outcome); cost utility (evaluates cost of treatment in relation to survival adjusted for quality of life,) and cost benefit (evaluates all clinical outcomes, such as prolonged life, in monetary terms). The most commonly used are cost-effectiveness and cost utility. The aim of this article is to provide the nonexpert reader with a basic understanding of these analyses, using pharmacoeconomic evaluations of clopidogrel for acute coronary syndromes as examples. Greater clinician understanding of pharmacoeconomic principles (and pitfalls) will enhance input of the physicians into the decision-making process to maximize the benefit of limited health care resources.

Using triple antiplatelet therapy in patients with non-ST elevation acute coronary syndrome managed invasively: a cost-effectiveness analysis

OBJECTIVES

To assess the incremental cost-effectiveness ratio (ICER) of glycoprotein IIb/IIIa (GPIIb/IIIa) inhibitors in patients with non-ST elevation acute coronary syndrome (NSTE-ACS) pretreated with aspirin and clopidogrel undergoing an early invasive treatment strategy.

METHODS

Cost-effectiveness analysis and cost-utility analysis were performed from a health-care system perspective, based on a Markov model with a time horizon of the patient life span. The risk of death and ischemic events was assessed using the Thrombolysis in Myocardial Infarction (TIMI) risk score. We compared three strategies: 1) routine upstream use of a GPIIb/IIIa inhibitor to all patients before angiography, 2) deferred selective use of abciximab in the catheterization laboratory just before angioplasty, and 3) double antiplatelet therapy without GPIIb/IIIa inhibitors. Both univariate sensitivity analysis and second-order probabilistic microsimulation were performed.

RESULTS

In the base case (65 years old, TIMI score 3), strategy A was the most effective, with an ICER of 15,150 euros per quality-adjusted life-year gained. Strategy B was dominated by a combination of strategies A and C. The ICER was very sensitive to the age and baseline risk of the patient. According to the widely accepted cost-effectiveness thresholds, strategy A would be cost-effective only in patients with an intermediate to high TIMI score, especially within the younger age groups. The probability that strategy A was cost-effective under the base case was 91.2%.

CONCLUSIONS

The use of GPIIb/IIIa inhibitors upstream in high-risk NSTE-ACS patients (TIMI score > or = 3) pretreated with aspirin and clopidogrel is cost-effective, particularly in the younger age groups.

The role of clopidogrel in revascularized and nonrevascularized patients with acute coronary syndromes

Despite many recent advancements in the treatment of coronary heart disease, it continues to be an important source of patient morbidity and mortality as well as a significant source of healthcare-related expenditures. Clopidogrel has become an integral part of the management of acute coronary syndromes (ACS) and, consequently, has become one of the world's best selling drugs. Numerous trials have demonstrated the clinical efficacy of clopidogrel in revascularized and nonrevascularized ACS including unstable angina as well as non-ST elevation and ST-elevation myocardial infarction. As a result of these trials, the use of clopidogrel has been incorporated into the American College of Cardiology/American Heart Association guidelines. Additionally, numerous analyses have proven clopidogrel to be highly cost effective. However, clopidogrel remains underutilized and guideline adherence remains inadequate despite the robust clinical data and guidelines. Institution of disease-management programs and quality-improvement initiatives appear to be an excellent strategy to promote guideline adherence and appropriate use of clopidogrel.

Clopidogrel bisulfate: in ST-segment elevation myocardial infarction

Clopidogrel bisulfate (hereafter, clopidogrel), a selective inhibitor of ADP-induced platelet aggregation, is approved for the reduction of atherothrombotic events in patients with ST-segment elevation myocardial infarction (STEMI). In COMMIT/CCS-2, a well designed trial in 45,852 adult patients with STEMI, relative to aspirin alone, clopidogrel 75 mg/day plus aspirin treatment significantly reduced the risk of both coprimary endpoints: the composite endpoint of reinfarction, stroke, or death from any cause and the risk of death from any cause. Based on the findings of this trial, treating 1000 patients for approximately 2 weeks with clopidogrel is associated with nine fewer patient deaths, reinfarctions, or strokes during treatment. In CLARITY-TIMI 28, a well designed supportive study in 3491 adult patients with STEMI, clopidogrel plus aspirin reduced the odds that a composite primary endpoint event of an occluded infarct-related artery, recurrent myocardial infarction, or death from any cause would occur versus aspirin plus placebo. Clopidogrel treatment was generally well tolerated in these clinical trials, with no significant between-group difference in the rate of major bleeding in either trial. Experience in other patient populations (e.g. those with recent myocardial infarction, recent ischemic stroke, or established peripheral arterial disease) has shown that longer-term (< or =3 years) clopidogrel monotherapy is generally well tolerated.