P620 Maintenance of clinical remission with SB5 biosimilar after switch from adalimumab originator: Real-life experience of a tertiary referral centre

Abstract

Abstract Background Adalimumab (ADM) biosimilars have been demonstrated as safe and effective as the ‘originator’ in trials for other autoimmune disorders, but real-life evidence in inflammatory bowel diseases (IBD) is lacking. The aim of the study was to demonstrate maintenance of clinical remission (CR) after switch from ADM ‘originator’ to biosimilar SB5. Methods Data were retrospectively collected from November 2018 to September 2019. All IBD patients in CR after at least 6 months of ‘originator’ and switched to SB5 were included. The primary outcomes were maintenance of CR at 6 months after switch (defined as Partial Mayo Score 0–1 for ulcerative colitis and Harvey–Bradshaw Index ≤4 for Crohn’s disease) and overall comparable safety. A historical cohort of patients treated only with the ‘originator’ was included for comparison, using a Cox regression model with a time-varying covariate. Results In total, 96 patients were included. Baseline characteristics of the cohort are reported in Table 1. Maintenance of CR after 6 months of switch was reported in 89/96 (92.7%) patients. Levels of C-reactive protein (CRP) significantly increased over time from baseline to 6 months (from 2.67 ± 2.61 to 4.98 ± 5.81 mg/dl, p = 0.03), but no difference between the two time points was found when considering a relevant flare only for CRP above the lab cut-off (5 mg/dl). A comparison of CR persistence over time between ‘originator’ cohort and SB5 ‘switching’ cohort did not show any statistical difference (Hazard Ratio 1.07, 95% CI 0.57 – 2.01). With regard to adverse events, SB5 showed an overall safety profile, with only 2/96 (2.1%) patients interrupting the treatment due to anti-TNF-induced psoriasis. In 42/96 (43.8%) of patients, at least one injection site reaction was reported; only in one case a re-switch to ‘originator’ was needed for local intolerance. Conclusion SB5 is safe and effective in maintaining CR after switching from the ‘originator’. Injection site reaction is a frequent but usually manageable side effect. Larger multi-centre cohort and endoscopic assessment are needed to confirm the initial findings.