Adaptive Bayesian Clinical Trial Design for Improving Robustness to Sample Size Calculation Assumptions: A Simulation Study Shirley Liao, Biogen; Fabio Pellegrini, Biogen International GmbH; Bernd Kieseier, Biogen; Christophe Hotermans, Biogen; Jason Mendoza, Biogen; Christine Lebrun, Centre Hospitalier Universitaire de Nice; Daniel Pelletier, University of Southern California; Aksel Siva, e Department of Neurology of Istanbul University, Cerrahpa?a School of Medicine; Maria Pia Sormani, Università degli Studi di Genova; Orhun Kantarci, Mayo Clinic ; Darin Okuda, UT Southwestern Medical Center; Carl de Moor, Biogen Inc