Emily L Johnson1, Yi-Ting Chang2, Barbara Davit2, Barry E Gidal2, Gregory L Krauss2. 1. From the Department of Neurology (E.L.J., G.L.K.), The Johns Hopkins University School of Medicine, Baltimore, MD; Johnson & Johnson (Y.-T.C.), New Brunswick; Merck & Co., Inc. (B.D.), Kenilworth, NJ; and University of Wisconsin (B.E.G.), School of Pharmacy, Madison, WI. ejohns92@jhmi.edu. 2. From the Department of Neurology (E.L.J., G.L.K.), The Johns Hopkins University School of Medicine, Baltimore, MD; Johnson & Johnson (Y.-T.C.), New Brunswick; Merck & Co., Inc. (B.D.), Kenilworth, NJ; and University of Wisconsin (B.E.G.), School of Pharmacy, Madison, WI.
Abstract
OBJECTIVES: The purpose of this study was to determine how closely generic modified-release antiepileptic drugs (MR-AEDs) resemble reference (brand) formulations by comparing peak concentrations (Cmax), total absorption (area under the curve [AUC]), time to Cmax (Tmax), intersubject variability, and food effects between generic and reference products. METHODS: We tabulated Cmax and AUC data from the bioequivalence (BE) studies used to support the approvals of generic Food and Drug Administration-approved MR-AEDs. We compared differences in 90% confidence intervals of the generic/reference AUC and Cmax geometric mean ratios, and intersubject variability, Tmax and delivery profiles and food effects. RESULTS: Forty-two MR-AED formulations were studied in 3,175 healthy participants without epilepsy in 97 BE studies. BE ratios for AUC and Cmax were similar between most generic and reference products: AUC ratios varied by >15% in 11.4% of BE studies; Cmax varied by >15% in 25.8% of studies. Tmax was more variable, with >30% difference in 13 studies (usually delayed in the fed compared to fasting BE studies). Generic and reference MR products had similar intersubject variability. Immediate-release AEDs showed less intersubject variability in AUC than did MR-AEDs. CONCLUSIONS: Most generic and reference MR-AEDs have similar AUC and Cmax values. Ratios for some products, however, are near acceptance limits and Tmax values may vary. Food effects are common with MR-AED products. High variability in pharmacokinetic values for once-a-day MR-AEDs suggests their major advantage compared to immediate-release AED formulations may be the convenience of less frequent dosing to improve adherence.
OBJECTIVES: The purpose of this study was to determine how closely generic modified-release antiepileptic drugs (MR-AEDs) resemble reference (brand) formulations by comparing peak concentrations (Cmax), total absorption (area under the curve [AUC]), time to Cmax (Tmax), intersubject variability, and food effects between generic and reference products. METHODS: We tabulated Cmax and AUC data from the bioequivalence (BE) studies used to support the approvals of generic Food and Drug Administration-approved MR-AEDs. We compared differences in 90% confidence intervals of the generic/reference AUC and Cmax geometric mean ratios, and intersubject variability, Tmax and delivery profiles and food effects. RESULTS: Forty-two MR-AED formulations were studied in 3,175 healthy participants without epilepsy in 97 BE studies. BE ratios for AUC and Cmax were similar between most generic and reference products: AUC ratios varied by >15% in 11.4% of BE studies; Cmax varied by >15% in 25.8% of studies. Tmax was more variable, with >30% difference in 13 studies (usually delayed in the fed compared to fasting BE studies). Generic and reference MR products had similar intersubject variability. Immediate-release AEDs showed less intersubject variability in AUC than did MR-AEDs. CONCLUSIONS: Most generic and reference MR-AEDs have similar AUC and Cmax values. Ratios for some products, however, are near acceptance limits and Tmax values may vary. Food effects are common with MR-AED products. High variability in pharmacokinetic values for once-a-day MR-AEDs suggests their major advantage compared to immediate-release AED formulations may be the convenience of less frequent dosing to improve adherence.
Authors: M R Nuwer; T R Browne; W E Dodson; F E Dreifuss; J Engel; I E Leppik; R H Mattson; J Penry; D M Treiman; B J Wilder Journal: Neurology Date: 1990-11 Impact factor: 9.910
Authors: Tricia Y Ting; Wenlei Jiang; Robert Lionberger; Jessica Wong; Jace W Jones; Maureen A Kane; Allan Krumholz; Robert Temple; James E Polli Journal: Epilepsia Date: 2015-07-23 Impact factor: 5.864