Switching from Infliximab Originator to SB2 Biosimilar in Inflammatory Bowel Diseases: A Multicentric Prospective Real-Life Study

Background: Current literature still lacks studies evaluating the effectiveness and safety of switching from Infliximab originator to SB2 biosimilar in Inflammatory Bowel Diseases (IBDs). We aimed to verify the ability of SB2 to maintain the clinical and biochemical response induced by originator after switching. As secondary outcome, we aimed to verify safety, tolerability and immunogenicity of SB2 biosimilar compared with its IFX originator. Methods: We prospectively enrolled all patients who switched from originator to SB2 at three Italian IBD Units from August 2018 to April 2020. We collected clinical and biochemical data at the time of switch (T0), and at the first (T1) and the second (T2) visits after switching (mean time from switching: 135 and 329 days, respectively). In addition, data regarding therapeutic drug monitoring at T0 and T1 were recorded. Results: Eighty-five IBD patients (28 with Ulcerative Colitis and 57 with Crohn's Disease) were included in the study. At T1, we observed statistically significant modifications in clinical activity of disease (70 patients were in clinical remission at baseline and 60 at T1 p = 0.02), but not at T2 (p = 0.3). Fecal calprotectin values were not different both at T1 and T2 (both p = 0.9) as well as the rate of concomitant treatment with steroids (p = 0.2 and p = 0.1) or immunosuppressants (p = 0.1 and p = 1.0). Moreover, the need for therapeutic optimization from T0 to T1 and from T1 to T2 was found significant (both p = 0.01). No anti-drug antibodies were identified at T1, and no serious adverse events were recorded. Conclusions: Overall, our data show that most of the patients switching from Infliximab originator to SB2 maintain the clinical and biochemical remission for at least 1 year. Further data are necessary to understand the clinical implications of these findings in the long term.