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Variability in Contraceptive Clinical Trial Design and the Challenges in Making Comparisons Across Trials

Clinical trials of contraceptives have often differed in their study designs, making cross-trial comparisons difficult. This brief report outlines some of the technical design features that can vary from trial to trial. For example, the overall number of menstrual cycles in a study has substantial i...

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Autores principales: Portman, David, Eisenberg, David L., Cason, Patty, Howard, Brandon
Formato: Online Artículo Texto
Lenguaje:English
Publicado: Springer Healthcare 2021
Materias:
Acceso en línea:https://www.ncbi.nlm.nih.gov/pmc/articles/PMC8520877/
https://www.ncbi.nlm.nih.gov/pubmed/34559358
http://dx.doi.org/10.1007/s12325-021-01915-3
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author Portman, David
Eisenberg, David L.
Cason, Patty
Howard, Brandon
author_facet Portman, David
Eisenberg, David L.
Cason, Patty
Howard, Brandon
author_sort Portman, David
collection PubMed
description Clinical trials of contraceptives have often differed in their study designs, making cross-trial comparisons difficult. This brief report outlines some of the technical design features that can vary from trial to trial. For example, the overall number of menstrual cycles in a study has substantial impact on the final efficacy determination; however, the rules related to qualifying cycles can differ based on the length of the study and the statistical analysis plan. In two commonly used methods of calculating efficacy, the Pearl Index and the time-to-event analysis, inclusion of fewer menstrual cycles results in higher calculated failure rates. Statistical analysis plans for contraceptive trials have sometimes excluded menstrual cycles because of an absence of documented vaginal intercourse and the concomitant use of another birth control method. Other design features that have varied between contraceptive trials relate to body mass index inclusion/exclusion criteria and the definition of “on-treatment” pregnancy. In addition, study designs of non-hormonal products can differ from those of hormonal products in their length and rules for qualifying cycles. The Draft Guidance for Hormonal Contraception, published in 2019 by the US Food and Drug Administration (FDA), will hopefully lead to more uniform trial design in the future, particularly for hormonal products. In the meantime, health care providers and patients should be aware of the nuances in trial design that make direct comparisons about relative efficacy challenging.
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spelling pubmed-85208772021-10-29 Variability in Contraceptive Clinical Trial Design and the Challenges in Making Comparisons Across Trials Portman, David Eisenberg, David L. Cason, Patty Howard, Brandon Adv Ther Commentary Clinical trials of contraceptives have often differed in their study designs, making cross-trial comparisons difficult. This brief report outlines some of the technical design features that can vary from trial to trial. For example, the overall number of menstrual cycles in a study has substantial impact on the final efficacy determination; however, the rules related to qualifying cycles can differ based on the length of the study and the statistical analysis plan. In two commonly used methods of calculating efficacy, the Pearl Index and the time-to-event analysis, inclusion of fewer menstrual cycles results in higher calculated failure rates. Statistical analysis plans for contraceptive trials have sometimes excluded menstrual cycles because of an absence of documented vaginal intercourse and the concomitant use of another birth control method. Other design features that have varied between contraceptive trials relate to body mass index inclusion/exclusion criteria and the definition of “on-treatment” pregnancy. In addition, study designs of non-hormonal products can differ from those of hormonal products in their length and rules for qualifying cycles. The Draft Guidance for Hormonal Contraception, published in 2019 by the US Food and Drug Administration (FDA), will hopefully lead to more uniform trial design in the future, particularly for hormonal products. In the meantime, health care providers and patients should be aware of the nuances in trial design that make direct comparisons about relative efficacy challenging. Springer Healthcare 2021-09-23 2021 /pmc/articles/PMC8520877/ /pubmed/34559358 http://dx.doi.org/10.1007/s12325-021-01915-3 Text en © The Author(s) 2021 https://creativecommons.org/licenses/by-nc/4.0/Open AccessThis article is licensed under a Creative Commons Attribution-NonCommercial 4.0 International License, which permits any non-commercial use, sharing, adaptation, distribution and reproduction in any medium or format, as long as you give appropriate credit to the original author(s) and the source, provide a link to the Creative Commons licence, and indicate if changes were made. The images or other third party material in this article are included in the article's Creative Commons licence, unless indicated otherwise in a credit line to the material. If material is not included in the article's Creative Commons licence and your intended use is not permitted by statutory regulation or exceeds the permitted use, you will need to obtain permission directly from the copyright holder. To view a copy of this licence, visit http://creativecommons.org/licenses/by-nc/4.0/ (https://creativecommons.org/licenses/by-nc/4.0/) .
spellingShingle Commentary
Portman, David
Eisenberg, David L.
Cason, Patty
Howard, Brandon
Variability in Contraceptive Clinical Trial Design and the Challenges in Making Comparisons Across Trials
title Variability in Contraceptive Clinical Trial Design and the Challenges in Making Comparisons Across Trials
title_full Variability in Contraceptive Clinical Trial Design and the Challenges in Making Comparisons Across Trials
title_fullStr Variability in Contraceptive Clinical Trial Design and the Challenges in Making Comparisons Across Trials
title_full_unstemmed Variability in Contraceptive Clinical Trial Design and the Challenges in Making Comparisons Across Trials
title_short Variability in Contraceptive Clinical Trial Design and the Challenges in Making Comparisons Across Trials
title_sort variability in contraceptive clinical trial design and the challenges in making comparisons across trials
topic Commentary
url https://www.ncbi.nlm.nih.gov/pmc/articles/PMC8520877/
https://www.ncbi.nlm.nih.gov/pubmed/34559358
http://dx.doi.org/10.1007/s12325-021-01915-3
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