ABSTRACT
I. INTRODUCTION Much of the statistical literature on interim analyses provides methodology by which studies, such as mortality trials, can be terminated early with adequate evidence of overwhelming efficacy. However, most of the drugs developed do not involve mortality studies. For such compounds, governmental regulations require the sponsoring company to document efficacy in well-controlled clinical studies and to demonstrate safety in a large number of patients followed for an extended period of time. As a result, sponsoring companies usually have little interest in terminating a trial early and filing a new drug application (NDA) based on the interim results.
