An urn based covariate adjusted response adaptive allocation design with dichotomous responses is proposed incorporating the ordered nature of the covariate. The allocation procedure is assessed both numerically and theoretically. The performance of the allocation design is also investigated in a relevant hypothetical clinical trial.
PongAChowSC. Overview of adaptive design methods in clinical trials. In: Handbook of adaptive designs in pharmaceutical and clinical development. Boca Raton, FL; New York: CRC Press, 2011.
2.
CoffeyCSKairallaJA. Adaptive clinical trials: progress and challenges. Drugs R & D2008; 9: 229–242.
3.
HuFRosenbergerWF. The theory of response-adaptive randomization in clinical trials. New York: Wiley Interscience, 2006.
4.
BandyopadhyayUBiswasA. Allocation by randomized play-the-winner rule in the presence of prognostic factors. Sankhya B1999; 61: 397–412.
5.
BandyopadhyayUBiswasA. Adaptive designs for normal responses with prognostic factors. Biometrika2001; 88: 409–419.
6.
BiswasAHuangHHHuangWT. Covariate-adjusted adaptive designs for continuous responses in a phase III clinical trial: recommendation for practice. J Biopharm Stat2006; 16: 227–239.
7.
BandyopadhyayUBiswasABhattacharyaR. Drop-the-loser design in the presence of covariates. Metrika2009; 69: 1–15.
8.
AtkinsonAC. Optimum biased coin designs for sequential clinical trials with prognostic factors. Biometrika1982; 69: 61–67.
9.
AtkinsonAC. The comparison of designs for sequential clinical trials with covariate information. J R Stat Soc A2002; 165: 349–373.
10.
AtkinsonACBiswasA. Adaptive biased-coin designs for skewing the allocation proportion in clinical trials with normal responses. Stat Med2005; 24: 2477–2492.
LiangYCarriereKC. Stratified and randomized play-the-winner rule. Stat Methods Med Res2008; 17: 581–593.
13.
TamuraRNFariesDEAndersenJS. A case study of an adaptive clinical trials in the treatment of out-patients with depressive disorder. J Am Stat Assoc 1994; 89: 768–776.
14.
FriedmanLMFurbergCDDeMetsDL. Fundamentals of clinical trials, 3rd ed. New York: Springer-Verlag, 1998.
15.
StoutWF. Almost sure convergence. New York: Academic Press, 1974.
