A0425
Title: Principal stratum strategy for safety evaluation
Authors: Veronica Ballerini - University of Florence (Italy) [presenting]
Alessandra Mattei - University of Florence (Italy)
Fabrizia Mealli - European University Institute (Italy)
Abstract: Safety evaluation of new therapies is an essential aspect of clinical trials, primarily quantifying the incidence of adverse events (AEs) and comparing it to a standard treatment. Despite its importance, safety analysis of adverse events is often rather simplistic: AE probabilities are estimated without explicitly defining the target causal comparison and neglecting assumptions on the censoring mechanisms, leading to differential follow-up times. A first proposal is made addressing the evaluation of drug safety in the estimand strategy framework under the principal stratification approach. Principal estimands of interest are defined; among them, the adherent incidence rate is introduced, namely the time-varying incidence rate of adverse events in the (time-varying) principal stratum of potential adherent patients. The principal effects are estimated under the assumption of principal ignorability leveraging a fully Bayesian model.
