Financial Analysis of CYP2C19 Genotyping in Patients Receiving Dual Antiplatelet Therapy Following Acute Coronary Syndrome and Percutaneous Coronary Intervention

AUTHORS: Samuel G. Johnson, Don Gruntowicz, Theresa Chua, Robert J. Morlock

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SUMMARY:

BACKGROUND: Dual antiplatelet therapy is an established standard of care for patients with acute coronary syndrome (ACS) to reduce thrombotic risk. Reduced CYP2C19 activity impairs clopidogrel bio-activation and increases risk of adverse clinical outcomes. Patients with poor and intermediate CYP2C19 metabolizers treated with clopidogrel incur higher cardiovascular event rates, including myocardial infarction, stroke, and stent thrombosis, following ACS than patients with normal CYP2C19 function. Tests are available to identify the CYP2C19 genotype and can be used to support individualization of antiplatelet therapy. 

OBJECTIVE: To estimate the financial impact of CYP2C19 genotyping in a theoretical cohort of 1,000 patients with ACS, who received percutaneous coronary intervention and coronary stent implantation and were treated with clopidogrel, prasugrel, or ticagrelor in a managed care setting. 

METHODS:Differences in overall and average cost per patient were estimated based on the rate of CYP2C19 genotyping in a theoretical cohort of 1,000 patients. Sensitivity analysis was carried out for varying costs, adherence, and the percentage of patients treated according to genotyping results. All clinical event costs were reported in terms of 2012 U.S. dollars. The budget impact analysis used published event rates from primary literature to estimate costs of events analysis for 3 different scenarios: Scenario A, no CYP2C19 genotyping; Scenario B, 50% of patients received CYP2C19 genotyping with appropriate treatment based on genotype; and Scenario C, 100% of patients received CYP2C19 genotyping with appropriate treatment based on genotype. 

RESULTS: According to this model, there was no change in the market share for the 3 antiplatelet agents in Scenario A. Initial market share for clopidogrel, prasugrel, and ticagrelor was 93%, 5%, and 2%, respectively; however, use of CYP2C19 genotyping is expected to shift market share from clopidogrel to either prasugrel or ticagrelor. In Scenario B, where 50% of the patients received genotyping, clopidogrel market share was reduced to 83%, while prasugrel increased to 12.1% and ticagrelor increased to 4.9%. In Scenario C, where all patients received genotyping, clopidogrel market share was reduced to 73%, prasugrel increased to 19.3%, and ticagrelor increased to 7.7%. Total estimated cost differences when all possible patients were genotyped included annual savings of roughly $444,852.

CONCLUSIONS: Important financial benefits may be realized through use of genotype-guided antiplatelet therapy to reserve prasugrel or ticagrelor use for patients with reduced CYP2C19 activity to avoid costs associated with adverse cardiac events.

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