Abstract: Clinical trials to evaluate the therapeutic effect of
pharmacological interventions are mostly conducted as double-blind comparative
studies. The study drug must prove its superiority over an active established
treatment (comparator) and/or a placebo. This traditional study design assumes
an additive relationship between pharmacological and placebo effects. Recent
research demonstrates that this model is probably not apt to establish the
therapeutic efficiency in clinical practice. The real therapeutic benefit of a
new drug becomes visible only through modifications and adaptations of the
study design that simulate the clinical treatment context. Such a modification
is seen in the introduction of an open verum treatment arm, in which
participants are certain to receive the study drug. This treatment realizes
expectancy effects that are inherent to clinical practice. The expectancy
effects are unspecified treatment effects and represent the placebo effect. The
aim of the open verum condition and the inherent optimized placebo effect is to
maximize the participants¡¯ therapeutic benefit through the improved
drug effect. Additionally, this procedure mimics clinical practice more
realistically and enables a more effective estimate of the therapeutic
efficiency of the drug under investigation. The drug's therapeutic
efficiency in clinical practice, including the expectancy effects, represents a
new but relevant criterion and objective for pharmacological research.