Comparison of the Lipid-lowering Effects of Generic Atorvastatin between Generic and Originator Brands

Abstract

Background: Generic drugs have the same therapeutic effect as original drugs. Generic drug substitution aimed at increasing opportunity of patients access to drugs and reducing drug expenditure.
At present, generic drugs of Atorvastatin manufactured by both originator company and generic company
as original-brand and generic-brand. Confidence in efficacy and safety of generic-brand substitution has limitation by health-care workers perception.Objective: This study was to compare lipid lowering effects of generic Atorvastatin between generic-brand and originator-brand with non-inferiority testing and was to report adverse drug events.Methods: A retrospective cohort study was conducted, and data collected from medical records. All patients were taking originator-brand of generic Atorvastatin at least 3 months and then divided into two groups, changed to generic-brand and continue originator-brand. Low-density lipoprotein cholesterols (LDL-C) was followed at 6 months and 1 year. The percent reduction from baseline in LDL-C was evaluated by multivariable Gaussian regression analysis. Non-inferiority hypothesis was evaluated at -5.94 mg/dL (non-inferiority margin).Results: Among 365 patients divided to generic-brand group (n=248) and originator-brand group (n=117). The percent reduction from baseline in LDL-C of  generic-brand and originator-brand was not significant, 1.60 mg/dL (95%CI: -4.92 to 8.13) at 6 months and 2.20 mg/dL (95%CI: -4.67 to 9.07) at 1 year. The 95% confidence interval was on the right side of non-inferiority margin, generic-brand was not inferior to originator-brand can be accepted. Adverse drug events needed to be confirmed because lack of report validity.Conclusion: Generic-brand substitution was accepted for efficacy. Adverse drug events should be monitored after generic drugs substitution.