Sample sizes for medical trials with special reference to long-term therapy

Halperin, Max; Rogot, Eugene; Gurian, Joan; Ederer, Fred

doi:10.1016/0021-9681(68)90082-9

Cited by 127 publications

(28 citation statements)

References 2 publications

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“…Several sample size formulas have been proposed for weighted logrank tests [29,[35][36][37]. In this section, we derive a sample size formula for the test MLR q .…”

Section: Sample Size Calculationmentioning

confidence: 99%

An omnibus test for several hazard alternatives in prevention randomized controlled clinical trials

Garès

Andrieu

Dupuy

et al. 2014

Statistics in Medicine

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The logrank test is optimal for testing the equality of survival distributions against a proportional hazards alternative. Under a late effects alternative, it is no longer appropriate, and one may turn to Fleming-Harrington's class of weighted logrank tests instead. In some settings, such as in preventive clinical trials where the statistical analysis has to be designed before the trial begins, it can be difficult to choose a priori between the logrank and Fleming-Harrington tests. A solution to this issue is provided. A decision rule is constructed for the problem of testing the equality of two survival distributions when the expected alternative may be one of the proportional hazards and late effects. A formula for computing the necessary sample size is obtained for this decision rule. A comprehensive simulation study is conducted to assess finite sample properties of the proposed test statistic. The proposed test improves both the logrank test and Fleming-Harrington's test for late effects. Finally, the methodology is illustrated on a data set in the field of prevention of Alzheimer's disease.

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“…Several sample size formulas have been proposed for weighted logrank tests [29,[35][36][37]. In this section, we derive a sample size formula for the test MLR q .…”

Section: Sample Size Calculationmentioning

confidence: 99%

An omnibus test for several hazard alternatives in prevention randomized controlled clinical trials

Garès

Andrieu

Dupuy

et al. 2014

Statistics in Medicine

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“…The reduction of the combined coronary endpoints was expected to be at most 10% in the conventional treatment group, and a 45% reduction in coronary events was assumed in the pravastatin group. A 20% drop-out rate over five years was assumed in both treatment groups (28).…”

Section: Design and Patientsmentioning

confidence: 99%

Pravastatin Use and Risk of Coronary Events and Cerebral Infarction in Japanese Men with Moderate Hypercholesterolemia : The Kyushu Lipid Intervention Study

Group¹

2000

J Atheroscler Thromb

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“…Its existence has long been noted and studied, for example, in Halperin et al (1968), Zucker & Lakatos (1990) and Chen et al (2002). Treatment saturation time is the time after which the full treatment effect starts to attenuate or diminish due to reasons such as cumulative buildup of drug resistance (Eshleman et al, 2001;Komarova & Wodarz, 2005;Wu et al, 2005).…”

Section: Introductionmentioning

confidence: 99%

Estimating a treatment effect with repeated measurements accounting for varying effectiveness duration

et al. 2007

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SummaryTo assess treatment efficacy in clinical trials, certain clinical outcomes are repeatedly measured over time for the same subject. These outcomes can be regarded as a function of time. The difference in their mean functions between the treatment arms usually characterises a treatment effect. Due to the potential existence of subject-specific treatment effectiveness lag and saturation times, erosion of treatment effect may occur during the observation period. Instead of using ad hoc parametric or purely nonparametric time-varying coefficients in statistical modeling, we first propose to model the treatment effectiveness durations, which are the varying time intervals between the lag and saturation times. Then some mean response models are used to include such treatment effectiveness durations. Our methodologies are demonstrated by simulations and an application to the dataset of a landmark HIV/AIDS clinical trial of short-course nevirapine against mother-to-child HIV vertical transmission during labour and delivery.

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Sample sizes for medical trials with special reference to long-term therapy

Cited by 127 publications

References 2 publications

An omnibus test for several hazard alternatives in prevention randomized controlled clinical trials

An omnibus test for several hazard alternatives in prevention randomized controlled clinical trials

Pravastatin Use and Risk of Coronary Events and Cerebral Infarction in Japanese Men with Moderate Hypercholesterolemia : The Kyushu Lipid Intervention Study

Estimating a treatment effect with repeated measurements accounting for varying effectiveness duration

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