In 4Q 2014, the Steering Committee of the International Council on Harmonization (ICH) endorsed the formation of an expert working group to develop an addendum to the ICH E9 guideline (Statistical Principles for Clinical Trials). The addendum was to focus on two topics involving clinical trials: estimands and sensitivity analyses. A draft of the addendum, referred to as E9/R1, was made available for public comments in 4Q 2017. In this presentation we will explain why the addendum was deemed necessary and describe the principles and framework articulated in the draft E9/R1. Case studies from the depression and diabetes therapeutic areas will be used to reinforce some key points. We will conclude by highlighting current gaps involving estimands and sensitivity analyses in commonly encountered clinical trial settings.