38 Group Sequential Design (POC and Phase III): Example Testing Strategy – 25% LB Analysi s Total Cases Observed Vaccine Cases Futility/ Failure Observed Vaccine Cases for Success Efficacy = 0% Efficacy = 25% Efficacy = 70% Cumulativ e Probabilit y of Failure (%) Cumulative Probability of Success (%) Cumulative Probability of Failure (%) Cumulativ e Probabilit y of Success (%) Cumulativ e Probabilit y of Failure (%) Cumulati ve Probabilit y of Success (%) 120  10 58.8133.470.77 235  15 666685.85<0.0159.380.121.2727.12 352  19  15 98.310.0286.470.632.6570.04 Final69  22  21 99.910.0997.622.386.5193.49 POC demonstration at 2 nd Interim Analysis (Observed VE >25%)