A new subcutaneous infliximab formulation is 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, double-blinded (Part 2 only), multicenter, parallel-group study was designed to evaluate Efficacy, Pharmacokinetics and Safety between Subcutaneous CT-P13 and Intravenous CT-P13 in Patients with Active RA.