This is a Phase 3, prospective, multicenter, placebo controlled, double blind, randomized
study to investigate the efficacy and safety of eculizumab in participants with severe GBS,
defined using the Hughes Functional Grade (FG) scale as progressively deteriorating FG3 or
FG4/FG5 within 2 weeks from onset of weakness due to GBS.
This study will be conducted only at sites in Japan.