P28 Update Efficacy and Futility Bounds at Time of Analysis in Group Sequential Designs

At the time of analyses of a group sequential design, there are scenarios where the efficacy/futility bounds need to be updated. This can occur when (1) the observed number of events differs from the planned numbers, (2) additional analyses are requested or skipped, or (3) the total alpha is changed due to an updated multiplicity graph. In such cases, the timing of the analyses deviates from the originally planned timing. While the literature covers the updating of boundaries under proportional hazards (PH) in gsDesign by Keaven Anderson, this poster will focus on updating the timing during analyses under non-proportional hazards (NPH). This topic is of significant interest to pharmaceutical practitioners who frequently observe delayed treatment effects.

group sequential designs

non-proportional hazards

futility tests

updated bounds 

Clinical Trial Design (e.g., Innovative/Complex Design, Estimands, Master Protocol)

ASA Biopharmaceutical Section Regulatory-Industry Statistics Workshop 2024