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Open Access 01-02-2020 | Levothyroxine | Letter to the Editor

Comment on: “Why Were More Than 200 Subjects Required to Demonstrate the Bioequivalence of a New Formulation of Levothyroxine with an Old One?”

Authors: Axel Krebs-Brown, Alain Munafo, Sumedh Gaikwad, Bogumila Urgatz, Claire Castello-Bridoux

Published in: Clinical Pharmacokinetics | Issue 2/2020

Excerpt

Having read with great interest the Current Opinion article by Concordet et al. [1] in this journal, we would like to comment on a number of points where we feel further clarification is required, or where we disagree with the authors’ statements about the Levothyrox^® trial [2]. …

Concordet D, Gandia P, Montastruc JL, Bousquet-Mélou A, Lees P, Ferran AA, et al. Why were more than 200 subjects required to demonstrate the bioequivalence of a new formulation of levothyroxine with an old one? Clin Pharmacokinet. 2019. https://doi.org/10.1007/s40262-019-00812-x(Epub 2019 Aug 21).CrossRefPubMedPubMedCentral

Gottwald-Hostalek U, Uhl W, Wolna P, Kahaly GJ. New levothyroxine formulation meeting 95–105% specification over the whole shelf-life: results from two pharmacokinetic trials. Curr Med Res Opin. 2017;33:169–74.CrossRef

Concordet D, Gandia P, Montastruc JL, Bousquet-Mélou A, Lees P, Ferran A, et al. Levothyrox^® new and old formulations: are they switchable for millions of patients? Clin Pharmacokinet. 2019;58(7):827–33. https://doi.org/10.1007/s40262-019-00747-3.CrossRefPubMedPubMedCentral

Munafo A, Krebs-Brown A, Gaikwad S, Urgatz B, Castello-Bridoux C. Comment on “Levothyrox^® new and old formulations: are they switchable for millions of patients?” [letter]. Clin Pharmacokinet. 2019;58(7):969–71. https://doi.org/10.1007/s40262-019-00785-x.CrossRefPubMedPubMedCentral

Concordet D, Gandia P, Montastruc J-L, Bousquet-Mélou A, Lees P, Ferran AA, et al. Authors’ reply to Castello-Bridoux et al.: “Comment on levothyrox^® new and old formulations: are they switchable for millions of patients?” [letter]. Clin Pharmacokinet. 2019;58(7):973–5. https://doi.org/10.1007/s40262-019-00786-w.CrossRefPubMedPubMedCentral

Davit BM, Nwakama PE, Buehler GJ, Conner DP, Haidar SH, Patel DT, et al. Comparing generic and innovator drugs: a review of 12 years of bioequivalence data from the United States Food and Drug Administration. Ann Pharmacother. 2009;43:1583–97.CrossRef

US FDA. Guidance for Industry: Statistical approaches to establishing bioequivalence. Final guidance. 2001. https://www.fda.gov/media/70958/download. Accessed 7 Sep 2019.

Hoenig JM, Heisey DM. The abuse of power: the pervasive fallacy of power calculations for data analysis. Am Stat. 2001;55(1):19–24.CrossRef

Michael R. Jiroutek: why it is nonsensical to use retrospective power analyses to conduct a postmortem on your study. J Clin Hypertens. 2018;20:408–10.CrossRef

10.

US FDA. Guidance for Industry: Bioavailability and bioequivalence studies submitted in NDAs or INDs—general considerations. Draft guidance. 2014. https://www.fda.gov/media/88254/download. Accessed 30 Aug 2019.

11.

Committee for Medicinal Products for Human Use (CHMP). Guideline on the investigation of bioequivalence. European Medicines Agency. 2010. https://www.ema.europa.eu/en/documents/scientific-guideline/guideline-investigation-bioequivalence-rev1_en.pdf. Accessed 30 Aug 2019.

Title: Comment on: “Why Were More Than 200 Subjects Required to Demonstrate the Bioequivalence of a New Formulation of Levothyroxine with an Old One?”
Authors: Axel Krebs-Brown
Alain Munafo
Sumedh Gaikwad
Bogumila Urgatz
Claire Castello-Bridoux
Publication date: 01-02-2020
Publisher: Springer International Publishing
Keyword: Levothyroxine
Published in: Clinical Pharmacokinetics / Issue 2/2020
Print ISSN: 0312-5963
Electronic ISSN: 1179-1926
DOI: https://doi.org/10.1007/s40262-019-00847-0

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Comment on: “Why Were More Than 200 Subjects Required to Demonstrate the Bioequivalence of a New Formulation of Levothyroxine with an Old One?”

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Keynote webinar | Spotlight on medication adherence

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