No abstract

SummaryA short review of placebo response in double-blind placebo-controlled therapeutic panic disorder studies published since 1985 is given. The main result is that the inefficacy-related drop-out rate of the placebo group of almost all clinical studies grows to more than 30% after 4-5 weeks of treatment and that often the results of placebo responders do not widely differ from that of the treatment groups. Except in some studies with very large sample sizes, the described response of the placebo group will not lead to significant differences between placebo and drug in completer analysis, making last observation carried forward (LOCF) analysis necessary. However, the large drop-out rates may lead to invalid efficacy results in later stages of the studies. As it can be shown that the inefficacy-related drop-out rates between placebo and target drug groups are as good an efficacy characteristic as any other, more conventional efficacy parameters, it is proposed to use the inefficacy related drop-out rate as the main efficacy parameter in placebo-controlled panic disorder studies of more than 4-5 weeks.

No abstract