Ivanova A, Rosenberger W F
Department of Biostatistics, The University of North Carolina at Chapel Hill, 27599-7400, USA.
J Biopharm Stat. 2000 Feb;10(1):93-107. doi: 10.1081/BIP-100101016.
Response-adaptive designs in clinical trials involve incorporating accruing information from patient responses to treatment into the randomization scheme in order to assign more patients to the treatment that has performed better in the trial up to that point. One probability model useful in generating an adaptive randomization scheme is an urn model. We will give a short overview of such adaptive models and compare four of them. We will be interested in how these four models minimize the number of treatment failures in a clinical trial with dichotomous response treatments. Comparison will be done via simulations for four treatments and exactly for three treatments for moderate sample sizes. We compare designs under the assumption that the results of treatments are known immediately, and we also allow some delay in response. Power is analyzed under various alternatives. Our results indicate that a birth and death urn with immigration is the best unless success probabilities are very small, in which case a randomized version of Polya's urn is preferred.
临床试验中的响应自适应设计涉及将患者对治疗的反应所积累的信息纳入随机化方案，以便将更多患者分配到截至当时在试验中表现更好的治疗组。一种用于生成自适应随机化方案的概率模型是瓮模型。我们将简要概述此类自适应模型并比较其中四种。我们将关注这四种模型如何在二分反应治疗的临床试验中使治疗失败的数量最小化。将通过模拟对四种治疗以及中等样本量下恰好三种治疗进行比较。我们在治疗结果立即已知的假设下比较设计，并且我们也允许反应有一定延迟。在各种替代方案下分析检验功效。我们的结果表明，除非成功概率非常小，否则带移民的生死瓮是最好的，在这种情况下，更倾向于使用随机化版本的波利亚瓮。
