An overview on clinical endpoints and estimands framework


Greta Brenna
Senior Biostatistician, PRINEOS srl, Milan


A very crucial step in designing a clinical trial is transforming the clinical research question in the most appropriate primary endpoint. Indeed, choosing the wrong primary endpoint can lead to an unsuccessful trial.
As already stated for the sample size calculation, the endpoints definition should also be outlined at the design stage of a clinical trial and requires a close cooperation between all the stakeholders involved (e.g., clinicians, statisticians, sponsors).
This article analyzes all the main endpoint characteristics with the aim of improving awareness and understanding of their definition.


The first concept to be clarified when discussing endpoints is the difference between objectives and endpoint or outcome measures.
The aim or the purpose of the study is usually defined as the primary clinical research question that the researchers are willing to investigate, that is the trial objective.