Treatment of Crohn's Disease

This is a multicenter, Phase 3, double-blind, placebo-controlled study evaluating the efficacy, safety, and tolerability of etrolizumab compared with placebo during induction and maintenance treatment of moderately to severely active Crohn's Disease (CD). The target population includes participants with CD who are refractory or intolerant to corticosteroids (CS) and/or immunosuppressant (IS) therapy and who have either not received prior anti-tumor necrosis factor (anti-TNF) therapy (TNF-naive) or who have had prior exposure to anti-TNF therapies and demonstrated inadequate responses or intolerance to anti-TNFs. The study period will consist of a Screening Phase (up to 35 days) plus (+) a 14-week Induction Phase + a 52-week Maintenance Phase + a 12-week Safety Follow-up Phase. At Week 14 (end of Induction Phase), participants achieving a decrease from baseline of at least 70 points in the Crohn's Disease Activity Index (CDAI) score (CDAI-70 response) without the use of rescue therapy will continue to the Maintenance Phase.