Reverse switching from the biosimilar SB2 to the originator infliximab in previously switched patients with inflammatory bowel diseases: results of a prospective long-term cohort study

Data regarding multiple switches including reverse switching between infliximab and its biosimilars are scarce in the field of inflammatory bowel diseases (IBD). We investigated the clinical effectiveness as primary outcome measure after repeated switches. Secondary endpoints included C-reactive protein (CRP) levels, immunogenicity (trough levels (TL); anti-drug antibodies (ADA), safety and drug persistence. This study is a prospective, single-centre, observational cohort study. IBD patients receiving originator infliximab were switched to biosimilar SB2 and then reverse switched after 96 weeks and followed up for another 48 weeks. Clinical disease activity (Harvey-Bradshaw-index (HBI) in Crohn's disease (CD), partial Mayo score (pMS) in ulcerative colitis (UC)), CRP, TL, ADA, therapy-discontinuations and (serious) adverse events ((S)AE)) were monitored throughout the study. Ninety-five patients (60 CD, 38 female) were enrolled. The median HBI was 2 (interquartile range (IQR) 1-4) at baseline and 2 (1-4) at week 48, resulting in a mean intra-individual change of 0.0 (standard deviation (SD) 1.5). The median pMS was 1 (IQR 0-1) at baseline and 0.5 (0-1) at week 48 resulting in a mean intra-individual change of 0.0 (SD 0.8). Clinical remission was achieved in 80% at baseline and 82% at week 48. Median CRP 2.0 mg/l (IQR 1.0-4.1) at baseline and 2.4 mg/l (1.1-5.2) at week 48 resulted in a mean change of 1.7 (SD 5.8) and no significant differences in CD ( = 0.3) and UC ( = 0.9). Median TL were 7.2 µg/ml (IQR 3.8-19.3) at baseline and 5.5 µg/ml (3.5-13.1) at week 48, resulting in a mean change of -1.0 (SD 7.4) with no statistical significance (CD = 0.26, UC = 0.41). De-novo-ADA were developed by 3.4%. The discontinuation rate was 14.7%. Safety signals were consistent with previous studies. Reverse switching had no impact on efficacy of infliximab therapy in our cohort of IBD patients. The switch didn't influence immunogenicity or safety of therapy.