  A group sequential clinical trial design can be an attractive option when
planning a pivotal trial as this approach has the ability to stop the trial
early for success, whilst also being well accepted from a regulatory review
perspective. Compared to a single stage design there are more moving parts to
consider and optimise when planning a group sequential trial. This tutorial
briefly outlines the group sequential methodology before detailing some of the
key operating characteristics and how these can be estimated, optimised and
ultimately presented to decision makers when aligning on a final study design.
