An optimal design in a two-stage ethical allocation based on U-statistics. Issue 8 (24th May 2022)

• Record Type: Journal Article
• Authors: Das, Radhakanta
• Is Part Of: Journal of statistical computation and simulation. Volume 92:Issue 8(2022)
• Page Start: 1763
• Page End: 1780
• Publication Date: 2022-05-24
• Subjects: Adaptive design -- clinical trial -- complete randomization rule -- two-stage ethical design; Mathematical statistics -- Data processing -- Periodicals; Digital computer simulation -- Periodicals; 519.5028505
• DOI: 10.1080/00949655.2021.2006658
• Languages: English
• ISSNs: 0094-9655

Abstract

Abstract : The present article is related to a comparison between two competing treatments, say A and B in the context of a Phase III clinical trial. This comparison is made through a U -statistic estimator of the functional θ = P ( X < Y ), where X and Y represent the continuous responses on treatments A and B respectively. Suppose the subjects are coming sequentially to a clinic and they are to be treated either by A or B . The recruitment of the subjects is done by following a two-stage ethical allocation design with an optimal sequential allocation at the first stage. Here a sequential sampling scheme with equal randomization is adopted to optimize the stage 1 sample size for a given the total sample size of the trial. Then, a response-adaptive randomization rule is employed at the second-stage with a view to achieve ethical gain measured in terms of the proportion of allocations on the better treatment. The motivation of the proposed two stage design is to assign a larger number of subjects to the more promising treatment. Here we study various asymptotic results associated with the proposed design and compare its performance with a single stage equal allocation design. Also, the proposed procedure is illustrated through a real-life data set on carcinoma in the oropharynx.