A new subcutaneous infliximab formulation is being developed by Celltrion, Inc. as an alternative to the intravenous regimen where subcutaneous infliximab injection typically takes less than 2 minutes. The availability of a subcutaneous formulation of infliximab would increase the treatment options available to patients, particularly those wishing to self-administer their therapy. This Phase I/III Study randomized, open-label, multicenter, parallel-group study is designed to Efficacy, Pharmacokinetics and Safety between Subcutaneous CT-P13 and Intravenous CT-P13 in Patients with Active Rheumatoid Arthritis.