<h3>Background</h3> CT-P13 is a biosimilar product of infliximab (INX). Data up to week 30 has been reported at EULAR 2012.¹ <h3>Objectives</h3> To compare the efficacy and safety of CT-P13 and INX in active rheumatoid arthritis (RA) patients up to week 54. <h3>Methods</h3> Patients with active RA (1987 ACR criteria) and inadequate response to methotrexate (MTX) were randomised (1:1) to receive either CT-P13 (3mg/kg) or INX (3mg/kg) at weeks 0, 2, 6 and then every 8 weeks up to week 54 in combination with MTX (12.5–25mg/week). <h3>Results</h3> Of 606 patients randomised at baseline, 457 patients were treated up to week 54. At week 54, ACR20 was highly similar between groups (CT-P13, 57.0% [172/302]; INX, 52.0% [158/304]; 95% CI: -0.03–0.13). ACR50 and ACR70 scores were also comparable between groups (CT-P13, 33.1% and 16.2%; INX, 31.6% and 15.1%, respectively). In the CT-P13 and INX groups respectively, 26.4% and 27.8% of patients reached remission with DAS28-CRP; additionally, 14.3% and 14.8% reached low disease activity compared to approximately 80% high disease activity in both groups at baseline. The proportion of patients testing positive for anti-drug antibodies (ADAs) was comparable between CT-P13 (52.3%) and INX (49.5%). More patients with negative ADA results achieved ACR20 responses (CT-P13, 73.9%; INX, 67.2%) compared with patients with positive results (CT-P13, 53.2%; INX, 48.1%). Total Sharp scores at baseline and week 54 were comparable (CT-P13, 104.6 and 70.4; INX, 103.6 and 73.0). C_max of CT-P13 or INX at all doses ranged from 66.1µg/mL–112.2µg/mL and 60.3µg/mL–104.5µg/mL, respectively. The safety profiles of CT-P13 and INX were also comparable (table). <h3>Conclusions</h3> CT-P13 showed comparable efficacy and PKs to those of INX up to week 54. CT-P13 was well tolerated with a safety profile comparable to that of INX up to week 54. <h3>References</h3> Yoo D <i>et al.</i> A randomized, double-blind, phase 3 study demonstrates clinical equivalence of CT-P13 to infliximab when co-administered with methotrexate in patients with active rheumatoid arthritis. Ann Rheum Dis 2012;71(Suppl 3):359. <h3>Disclosure of Interest</h3> D. H. Yoo Consultant for: CELLTRION Inc., A. Racewicz Grant/research support from: CELLTRION Inc., J. Brzezicki Grant/research support from: CELLTRION Inc., R. Yatsyshyn Grant/research support from: CELLTRION Inc., E. Tobias Arteaga Grant/research support from: CELLTRION Inc., A. Baranauskaite Grant/research support from: CELLTRION Inc., C. Abud-Mendoza Grant/research support from: CELLTRION Inc., S. Navarra Grant/research support from: CELLTRION Inc., Consultant for: Pfizer Ltd., Speakers bureau: CELLTRION Inc., R. Eullaran Grant/research support from: CELLTRION Inc., V. Kadinov Grant/research support from: CELLTRION Inc., I. Goecke Sariego Grant/research support from: CELLTRION Inc., P. Byrne Grant/research support from: CELLTRION Inc., W. Park Consultant for: CELLTRION Inc., S. J. Lee Consultant for: CELLTRION Inc., Employee of: CELLTRION Inc., H. U. Kim Employee of: CELLTRION Inc., U. Müller-Ladner Speakers bureau: CELLTRION Inc.