Dose-response studies play an important role in many applications. Particularly in pharmaceutical drug development the assessment of a dose-related effect and the subsequent estimation of a target dose are of central importance. Clinical dose-finding studies are designed to investigate the effect of a given drug at several doses, possibly in comparison with a placebo group or an active control. Current clinical practice typically aims at two major goals when performing a dose-finding study (Ruberg, 1995a, 1995b; Bretz et al., 2008):

• First, one is interested in assessing an overall dose-response effect. The aim is thus to ensure that, by changing the dose, the response (efficacy and/or safety) changes as well.