  This paper addresses the problem of deciding whether the dose response
relationships between subgroups and the full population in a multi-regional
trial are similar to each other. Similarity is measured in terms of the maximal
deviation between the dose response curves. We consider a parametric framework
and develop two powerful bootstrap tests for the similarity between the dose
response curves of one subgroup and the full population, and for the similarity
between the dose response curves of several subgroups and the full population.
We prove the validity of the tests, investigate the finite sample properties by
means of a simulation study and finally illustrate the methodology in a case
study.
