Introduction: SB2 is a biosimilar of infliximab (IFX), which is approved for rheumatoid arthritis (RA), ankylosing spondylitis (AS), adult and pediatric Crohn's disease (CD), adult and pediatric ulcerative colitis (UC), psoriatic arthritis (PsA), and plaque psoriasis (PsO). The drug approval process in Korea includes postmarketing surveillance (PMS) studies to re-examine the safety and effectiveness of approved new medications. Methods: This was a prospective, multi-center, open-label, observational, phase 4 PMS study of IFX-naı ¨ve patients or patients switched from reference IFX or another IFX-biosimilar to SB2 in all approved indications.