CT-P13 (Infliximab) is a monoclonal antibody currently being developed by CELLTRION, Inc. This open-label, single-arm, multicenter, multiple single dose intravenous (IV) infusion, efficacy, and safety extension study of the Phase 3 Study CT-P13 3.1 is designed to assess the long-term efficacy and safety of multiple doses of CT-P13.