On statistical analysis for placebo-challenging designs in clinical trials

In clinical trials, appropriate designs are often chosen to address scientific/medical questions of particular interest to the investigator. For a chosen statistical design, however, standard statistical procedures may not be applicable owing to the nature of the design. In this paper we examine statistical methods for analysis of data collected from a placebo-challenging design which is often considered for assessment of the efficacy of drug products for indication of erectile dysfunction. An example concerning a clinical trial conducted with 120 male patients with erectile dysfunction is used to illustrate the derived statistical methods. Some recommendations to the randomization procedure for the study design of this kind are also made.