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Journal ArticleDOI

A comparison between two treatments in a clinical trial with an ethical allocation design

TL;DR: In this paper, the authors compared two treatments, say A and B, in the context of a clinical trial using the Mann-Whitney-Wilcoxon (MWW) statistic.
Abstract: The present article compares two treatments, say A and B, in the context of a clinical trial. Let X and Y be, respectively, the responses corresponding to A and B which have some continuous distributions. Here, the comparison is done through the parameter θ=P(X
Citations
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Journal ArticleDOI
TL;DR: A flexible method of extending a study based on conditional power, where the significance of the treatment difference at the planned end is used to determine the number of additional observations needed and the critical value necessary after accruing those additional observations.

252 citations

Journal ArticleDOI
TL;DR: In this article, the authors provided a statistical inference on comparative performances of two treatments in a clinical trial under a two-stage adaptive allocation design, where a fixed number (2m+n, say) of subjects are available for treatment by any of the two competing treatments, for a particular ailment.
Abstract: The present article provides a statistical inference on comparative performances of two treatments in a clinical trial under a two-stage adaptive allocation design Suppose a fixed number (2m+n, say) of subjects are available for treatment by any of the two competing treatments, say, A and B for a particular ailment As per the proposed allocation design, 2m incoming subjects are randomised equally between A and B at the first stage Then, at the second stage, the remaining n subjects are exclusively assigned to the treatment which has higher observed median response evaluated in the first stage Under such an ethical allocation design we decide on the better treatment through an asymptotically distribution-free test procedure The related asymptotic results are also studied

1 citations


Cites methods from "A comparison between two treatments..."

  • ...Using this design Bandyopadhyay and Das (2008, 2017) have derived some methods based on Mann–Whitney U-statistic for selecting the better treatment....

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Journal ArticleDOI
TL;DR: In this paper , a distribution-free test procedure for comparing the effectiveness of two competing treatments A and B, say, in a clinical trial, is provided, where the relative treatment effect is measured by the functional θ=P(X
Abstract: The present article provides a distribution-free test procedure for comparing the effectiveness of two competing treatments A and B, say, in a clinical trial. Here, the relative treatment effect is measured by the functional θ=P(X
References
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Journal ArticleDOI
TL;DR: A randomized two-stage adaptive design for allocation of patients to treatments and comparison in a phase III clinical trial with survival time as treatment responses and the possibility of several covariates is considered.
Abstract: A randomized two-stage adaptive design is proposed and studied for allocation of patients to treatments and comparison in a phase III clinical trial with survival time as treatment responses. We consider the possibility of several covariates in the design and analysis. Several exact and limiting properties of the design and the follow-up inference are studied, both numerically and theoretically. The applicability of the proposed methodology is illustrated by using some real data.

17 citations


"A comparison between two treatments..." refers background in this paper

  • ...[31,32] have considered the two-stage adaptive design in the context of clinical trials with survival data....

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Journal ArticleDOI
TL;DR: A simulation program is presented which covers a wide range of adaptive scenarios in two stage designs and allows to estimate statistical properties of particular adaptation rules and applications to dose finding problems in clinical trials are demonstrated.

17 citations


"A comparison between two treatments..." refers methods in this paper

  • ...For theories and logistics of two-stage designs, one can also go through the work by, among others, Bauer, Bauer and Buddle [20], Bauer, Brannath and Posch [21], Liu et al. [22], Ivanova et al. [23], Dette et al. [24], Shan et al. [25] and Xu and Yin [26]....

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  • ...For theories and logistics of two-stage designs, one can also go through the work by, among others, Bauer, Bauer and Buddle [20], Bauer, Brannath and Posch [21], Liu et al....

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Journal Article
TL;DR: In this article, a randomized two-stage adaptive design is proposed and studied for allocation of patients to treatments and comparison in a phase III clinical trial with survival time as treatment responses.
Abstract: A randomized two-stage adaptive design is proposed and studied for allocation of patients to treatments and comparison in a phase III clinical trial with survival time as treatment responses. We consider the possibility of several covariates in the design and analysis. Several exact and limiting properties of the design and the follow-up inference are studied, both numerically and theoretically. The applicability of the proposed methodology is illustrated by using some real data.

16 citations

Journal ArticleDOI
TL;DR: In this article, the authors compare the performance of two adaptive designs and equal allocation in a clinical trial with two highly successful treatments and binary outcomes, and find that the urn model produces a better procedure than the sequential maximum likelihood approach and equal assignment, in that it yields fewer expected treatment failures, maintains the power of the asymptotic test, and is more powerful when the Fisher's exact test is used.
Abstract: We compare the performance of two adaptive designs and equal allocation in a clinical trial with two highly successful treatments and binary outcomes. The measure of interest in the trial is the odds ratio. The goal of the adaptive design is to decrease the total number of failures compared to equal allocation while keeping the power at the same level. One design is based on sequential maximum likelihood estimation, the other on an urn model. We find that the urn model produces a better procedure than the sequential maximum likelihood approach and equal allocation, in that it yields fewer expected treatment failures, maintains the power of the asymptotic test, and is more powerful when the Fisher's exact test is used. We conclude that adaptive designs have attractive properties when both treatments are highly successful.

16 citations

Journal ArticleDOI
TL;DR: A Bayesian adaptive two-stage design for the efficient estimation of the maximum dose or the minimum effective dose in a dose-finding trial that allocates subjects in stage two according to the posterior distribution of the target dose location.
Abstract: We propose a Bayesian adaptive two-stage design for the efficient estimation of the maximum dose or the minimum effective dose in a dose-finding trial. The new design allocates subjects in stage two according to the posterior distribution of the target dose location. Simulations show that the proposed two-stage design is superior to equal allocation and to a two-stage strategy where only one dose is left in the second stage.

15 citations