title: An objective re-evaluation of adaptive sample size re-estimation: commentary on 'Twenty-five years of confirmatory adaptive designs'.
abstract: Over the past 25 years, adaptive designs have gradually gained acceptance and are being used with increasing frequency in confirmatory clinical trials. Recent surveys of submissions to the regulatory agencies reveal that the most popular type of adaptation is unblinded sample size re-estimation. Concerns have nevertheless been raised that this type of adaptation is inefficient.We intend to show in our discussion that such concerns are greatly exaggerated in any practical setting and that the advantages of adaptive sample size re-estimation usually outweigh any minor loss of efficiency.
authors.affiliation: Cytel Corporation, 675 Massachusetts Avenue, Cambridge, MA, 02139, U.S.A.|Harvard T.H. Chan School of Public Health, 677 Huntington Avenue, Boston, MA, 02115, U.S.A.
authors.forename: Cyrus
authors.initials: C
authors.lastname: Mehta
authors.affiliation: Cytel Corporation, 675 Massachusetts Avenue, Cambridge, MA, 02139, U.S.A.
authors.forename: Lingyun
authors.initials: L
authors.lastname: Liu
mesh_terms: D002986:Clinical Trials as Topic; D006801:Humans; D012107:Research Design; D018401:Sample Size
keywords: adaptive versus group sequential designs; efficiency of adaptive designs; promising-zone designs