Sequential treatment allocation procedures in clinical trials-with particular attention to the analysis of results for the biased coin design

1986 ◽  
Vol 5 (3) ◽  
pp. 211-229 ◽  
Author(s):  
Jerry Halpern ◽  
Byron Wm. Brown
Keyword(s):  
Clinical Trials ◽  
Sequential Treatment ◽  
Treatment Allocation ◽  
Biased Coin Design ◽  
Analysis Of Results ◽  
Biased Coin

Generalized Efron's biased coin design and its theoretical properties

2016 ◽  
Vol 53 (2) ◽  
pp. 327-340 ◽  
Author(s):  
Yanqing Hu
Keyword(s):  
Clinical Trials ◽  
General Theory ◽  
Convergence Rate ◽  
Biased Coin Design ◽  
Target Ratio ◽  
Allocation Ratio ◽  
Target Allocation ◽  
Biased Coin

Abstract In clinical trials with two treatment arms, Efron's biased coin design, Efron (1971), sequentially assigns a patient to the underrepresented arm with probability p > ½. Under this design the proportion of patients in any arm converges to ½, and the convergence rate is n-1, as opposed to n-½ under some other popular designs. The generalization of Efron's design to K ≥ 2 arms and an unequal target allocation ratio (q1, . . ., qK) can be found in some papers, most of which determine the allocation probabilities ps in a heuristic way. Nonetheless, it has been noted that by using inappropriate ps, the proportion of patients in the K arms never converges to the target ratio. We develop a general theory to answer the question of what allocation probabilities ensure that the realized proportions under a generalized design still converge to the target ratio (q1, . . ., qK) with rate n-1.

Sequential treatment allocation in clinical trials

Biometrika ◽  
1971 ◽  
Vol 58 (3) ◽  
pp. 419-426 ◽  
Author(s):  
B. J. FLEHINGER ◽  
T. A. LOUIS
Keyword(s):  
Clinical Trials ◽  
Sequential Treatment ◽  
Treatment Allocation

Adaptive Designs for Non-inferiority Trials with Multiple Experimental Treatments

2017 ◽  
Vol 27 (11) ◽  
pp. 3255-3270 ◽  
Author(s):  
Wenfu Xu ◽  
Feifang Hu ◽  
Siu Hung Cheung
Keyword(s):  
Clinical Trials ◽  
Adaptive Design ◽  
Treatment Allocation ◽  
Balanced Design ◽  
Adaptive Treatment ◽  
Biased Coin Design ◽  
New Treatment ◽  
Experimental Treatments ◽  
Treatment Comparisons ◽  
New Treatments

The increase in the popularity of non-inferiority clinical trials represents the increasing need to search for substitutes for some reference (standard) treatments. A new treatment would be preferred to the standard treatment if the benefits of adopting it outweigh a possible clinically insignificant reduction in treatment efficacy (non-inferiority margin). Statistical procedures have recently been developed for treatment comparisons in non-inferiority clinical trials that have multiple experimental (new) treatments. An ethical concern for non-inferiority trials is that some patients undergo the less effective treatments; this problem is more serious when multiple experimental treatments are included in a balanced trial in which the sample sizes are the same for all experimental treatments. With the aim of giving fewer patients the inferior treatments, we propose a response-adaptive treatment allocation scheme that is based on the doubly adaptive biased coin design. The proposed adaptive design is also shown to be superior to the balanced design in terms of testing power.

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