Biostatistics Weekly Seminar

An objective of phase 3 preventive COVID-19 vaccine efficacy trials is to assess immunological biomarkers measured post-vaccination as surrogate endpoints that can constitute the basis for traditional or accelerated approval for the tested vaccine and for other vaccines in the same class. Evidence supporting reliable use of biomarkers for such approval approaches may be based on a synthesis of results from a variety of types of statistical analyses of phase 3 trial data, combined with external data on evidence for biomarkers as mechanisms of protection (e.g., from vaccine challenge studies in animals, from passive antibody transfer challenge studies in animals or humans, and from passive antibody transfer phase 3 trials). In this talk I will summarize current thinking of COVID-19 Prevention Trials Network statisticians on statistical methodological approaches for evaluating the validity of candidate surrogate endpoints from phase 3 trial data. Issues addressed include immunological biomarker sampling design, immunological biomarker selection and optimization, methods for combining biomarkers to develop best predictors of study outcomes, principal stratification approaches to assessing vaccine efficacy moderation, causal mediation approaches to assessing the proportion of vaccine efficacy mediated through one or more biomarkers, a causal intervention approach that addresses how much outcome risk would be altered by stochastically shifting the biomarker distribution upwards, and meta-analysis of a set of phase 3 trials.

Zoom (Link to Follow)
30 September 2020
1:30pm