text_1: 预先 设定 的 疗效 终止 规则 是 基于 应用 O ' Brien - Fleming a 消耗 函数 的 Lan - DeMets 程序 .
  
text_2: the prespecified stopping rule for efficacy was based on the Lan @-@ DeMets procedure with the O 'Brien @-@ Fleming alpha @-@ spending function .
  