Asymmetric Group Sequential Boundaries for Monitoring Clinical Trials
提出一种非对称组序贯边界方法，用于治疗-安慰剂试验的期中分析，结合了早期停止和严格检验的要求，帮助研究者判断是否提前终止试验。
A group sequential method is proposed for the periodic analysis of accumulating data in clinical trials which are essentially one-sided as in treatment-placebo studies. The proposed boundaries retain the early stopping properties of the procedure described previously by DeMets & Ware (1980) when treatment appears to be ineffective or harmful but incorporate the more stringent requirements of the model proposed by O'Brien & Fleming (1979) for early rejection of the null hypothesis in favour of treatment.