Safety and Effectiveness of SB2 (Infliximab Biosimilar) in Adult Patients with Immune-Mediated Inflammatory Diseases: A Post-Marketing Surveillance in Korea

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 post-marketing 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-naïve patients or patients switched from reference IFX or another IFX-biosimilar to SB2 in all approved indications. The primary endpoint was to evaluate the safety of SB2 reported as adverse events (AEs) and adverse drug reactions (ADRs). The secondary endpoint was to evaluate the effectiveness measured as investigators' overall effectiveness assessment, categorized as improved, stable, or worsened. Furthermore, disease-specific activity scores were collected for each indication [28-joint Modified Disease Activity Score (DAS28) for RA, Korean Bath Ankylosing Spondylitis Disease Activity Index (KBASDAI), Crohn’s Disease Activity Index (CDAI), and Full Mayo Score for UC]. Results: In the safety and effectiveness analysis, 180 and 128 patients were included, respectively. Most patients (83.9%) were IFX-naïve patients and 16.1% were switched patients. RA (48.9%) and AS (31.1%) were the most frequent indications. Overall, 23 (12.8%) patients reported AEs and 14 (7.8%) patients reported ADRs. Serious adverse events (SAEs) were reported by 3 (1.7%) patients. As per investigators’ overall effectiveness assessments, SB2 was effective in 94.6% (105/111) of IFX-naïve patients and 82.4% (14/17) of switched patients. In IFX-naïve patients, disease activity scores decreased significantly from baseline to week 30 (week 24 for AS); mean (SD) changes of disease scores for each indication were DAS28 − 1.9 (0.79) for RA, KBASDAI − 3.8 (1.68) for AS, CDAI − 200.4 (112.47) for CD, and Full Mayo Score − 6.6 (2.92) for UC. The persistence rate of SB2 treatments was 88.3% with median treatment duration of 30.1 weeks. Conclusion: This PMS study of the IFX-biosimilar SB2 in Korea confirmed the safety and effectiveness of SB2 in major indications.