Joshua J Gagne1, Jennifer M Polinski1, Wenlei Jiang2, Sarah K Dutcher2, Jing Xie1, Joyce Lii1, Lisa A Fulchino1, Aaron S Kesselheim1. 1. Program on Regulation, Therapeutics, And Law (PORTAL), Division of Pharmacoepidemiology and Pharmacoeconomics, Department of Medicine, Brigham and Women's Hospital and Harvard Medical School, Boston, MA, USA. 2. Office of Generic Drugs, Center for Drug Evaluation and Research, US Food and Drug Administration, Silver Spring, MD, USA.
Abstract
PURPOSE: US Food and Drug Administration approval for generic drugs relies on demonstrating pharmaceutical equivalence and bioequivalence; however, some drug products have unique attributes that necessitate product-specific approval pathways. We evaluated rates of patients' switching back to brand-name versions from generic versions of four drugs approved via such approaches. METHODS: We used data from Optum LifeSciences Research Database to identify patients using a brand-name version of a study drug (acarbose tablets, salmon calcitonin nasal spray, enoxaparin sodium injection, and venlafaxine extended release tablets) or a control drug. We followed patients to identify switching to generic versions and then followed those who switched to identify whether they switched back to brand-name versions. We calculated switch and switch-back rates and used Kaplan-Meier and log-rank tests to compare rates between study and control drugs. RESULTS: Our cohort included 201 959 eligible patients. Brand-to-generic switch rates ranged from 66 to 106 switches per 100 person-years for study drugs and 80 to 110 for control drugs. Rates of switch-back to brand-name versions ranged from 5 to 37 among study drugs and 3 to 53 among control drugs. Switch-back rates were higher for venlafaxine vs. sertraline (p < 0.01) and calcitonin vs. alendronate (p = 0.01). Switch-back rates were lower for venlafaxine vs. paroxetine (p < 0.01) and acarbose vs. nateglinide (p < 0.01). Rates were similar for acarbose vs. glimepiride (p = 0.97) and for enoxaparin vs. fondiparinux (p = 0.11). CONCLUSION: As compared to control drugs, patients were not more likely to systematically switch back from generic to brand-name versions of the four study drugs.
PURPOSE: US Food and Drug Administration approval for generic drugs relies on demonstrating pharmaceutical equivalence and bioequivalence; however, some drug products have unique attributes that necessitate product-specific approval pathways. We evaluated rates of patients' switching back to brand-name versions from generic versions of four drugs approved via such approaches. METHODS: We used data from Optum LifeSciences Research Database to identify patients using a brand-name version of a study drug (acarbose tablets, salmon calcitonin nasal spray, enoxaparin sodium injection, and venlafaxine extended release tablets) or a control drug. We followed patients to identify switching to generic versions and then followed those who switched to identify whether they switched back to brand-name versions. We calculated switch and switch-back rates and used Kaplan-Meier and log-rank tests to compare rates between study and control drugs. RESULTS: Our cohort included 201 959 eligible patients. Brand-to-generic switch rates ranged from 66 to 106 switches per 100 person-years for study drugs and 80 to 110 for control drugs. Rates of switch-back to brand-name versions ranged from 5 to 37 among study drugs and 3 to 53 among control drugs. Switch-back rates were higher for venlafaxine vs. sertraline (p < 0.01) and calcitonin vs. alendronate (p = 0.01). Switch-back rates were lower for venlafaxine vs. paroxetine (p < 0.01) and acarbose vs. nateglinide (p < 0.01). Rates were similar for acarbose vs. glimepiride (p = 0.97) and for enoxaparin vs. fondiparinux (p = 0.11). CONCLUSION: As compared to control drugs, patients were not more likely to systematically switch back from generic to brand-name versions of the four study drugs.
Authors: Richard A Hansen; Jingjing Qian; Richard Berg; James Linneman; Enrique Seoane-Vazquez; Sarah K Dutcher; Saeid Raofi; C David Page; Peggy Peissig Journal: Pharmacotherapy Date: 2017-03-20 Impact factor: 4.705
Authors: Joshua J Gagne; Jennifer R Popovic; Michael Nguyen; Sukhminder K Sandhu; Patty Greene; Rima Izem; Wenlei Jiang; Zhong Wang; Yueqin Zhao; Andrew B Petrone; Anita K Wagner; Sarah K Dutcher Journal: Drug Saf Date: 2018-12 Impact factor: 5.606
Authors: Joshua J Gagne; Jennifer M Polinski; Wenlei Jiang; Sarah K Dutcher; Jing Xie; Joyce Lii; Lisa A Fulchino; Aaron S Kesselheim Journal: Drugs Date: 2017-03 Impact factor: 9.546
Authors: Aaron S Kesselheim; Wesley Eddings; Tara Raj; Eric G Campbell; Jessica M Franklin; Kathryn M Ross; Lisa A Fulchino; Jerry Avorn; Joshua J Gagne Journal: PLoS One Date: 2016-10-21 Impact factor: 3.240