ABSTRACT
The results of sequential analyses in Table 4 demonstrate that all boundaries are crossed at the fourth analysis, with a total of 176 deaths observed. The cumulative deaths are 69 and 107, respectively, in the Blocadren and placebo groups with a hazard ratio r = 0.63. The corresponding z scores for the logrank, Peto-Prentice Wilcoxon, and Tarone-Ware tests at the fourth analysis are, respectively, 3.061, 2.967, and 2.836, which exceed all boundaries values at a = 0.05 level. Note that the logrank z score also exceeds all boundary values at a = 0.01. Therefore, based on the fixed-time analysis, the trial would be again recommended for termination at the fourth analysis as of January 20, 1980 (on day 737 of the trial).
