Considerations for the planning, conduct and reporting of clinical trials with interim analyses

Interim analyses are prevalent in clinical trials. Although methodology is well established, there are aspects of how to operationalize and interpret interim analyses which remain unclear to many stakeholders. In this paper, a team of statisticians from the pharmaceutical industry, academia, and regulatory agencies provide a multi-stakeholder perspective on the key concepts behind interim analyses and considerations on terminology. We illustrate our proposals using a hypothetical clinical trial.