Covariate-adjusted adaptive designs for continuous responses in a phase III clinical trial: recommendation for practice.
One adaptive design is proposed and studied by Bandyopadhyay and Biswas (2001) for comparing two treatments having continuous responses with covariates at hand in a phase III clinical trial. On the other hand, a drop-the-loser urn design is recently proposed by Ivanova (2003), which is known to have the least variability among urn-based adaptive designs for binary responses. The drop-the-loser rule for continuous data was recently introduced by Ivanova et al. (2005). But neither of the works considered covariates for the allocation design. The present paper provides a version of the newly proposed adaptive design, drop-the-loser rule, but for continuous responses and by incorporating the covariate information in the allocation procedure. Several exact and limiting properties of the design, and also of a simpler version of it, are studied. We compare the design of Bandyopadhyay and Biswas (2001) with the covariate-adjusted drop-the-loser-type rule for continuous responses and conclude that, although the drop-the-loser rule is better for binary responses, the design of Bandyopadhyay and Biswas (2001) performs better than the drop-the-loser-type rule for continuous responses with covariates. We recommend the existing design of Bandyopadhyay and Biswas (2001) for practical purposes.
Applied Statistics Unit, Indian Statistical Institute, 203 B.T. Road, Kolkata 700 035, India. atanu@isical.ac.in
Atanu
A
Biswas
Hui-Hsin
HH
Huang
Wen-Tao
WT
Huang
D017326:Clinical Trials, Phase III as Topic / Q000706:statistics & numerical data*; D003198:Computer Simulation; D005473:Fluoxetine / Q000627:therapeutic use; D006801:Humans; D015233:Models, Statistical; D015999:Multivariate Analysis; D012107:Research Design
D005473:Fluoxetine