Background: First biosimilar infliximab (IFX) has been approved in European Union for treatment of inflammatory bowel disease (IBD) since September 2013. The approval process included extrapolation of clinical data from other indications, namely rheumatoid arthritis and ankylosing spondylitis. Data from clinical practice are therefore desirable to confirm efficacy and safety of biosimilar IFX in IBD population.
Despite growing data on early treatment results, the evidence on long-term efficiency and safety of maintenance treatment with biosimilar IFX in patients with IBD is only sparse.
Methods: Data from consecutive patients with CD and UC starting on biosimilar IFX between January 2015 and May 2016 at our center were analyzed. Patients were assessed as non-responders (NR), partial responders (PR), or complete responders (CR) based on clinical, endoscopic, and laboratory parameters. Besides clinical and endoscopic evaluation, C-reactive protein (CRP) levels, faecal calprotectin (FC), blood count, IFX trough levels (TL), and antibodies-to-infliximab (ATI) were measured. All adverse events were recorded. Final analysis was performed at week 54 (W54).
Results: One hundred forty IBD patients (CD, 107; UC, 33) were included into the analysis. In total, 94% of CD and 82% of UC patients responded to induction therapy (W14) with biosimilar IFX. At W54 the response rates were 87% in CD and 60% in UC and 47% and 36% of patients, respectively, were in remission.
Fifty two percent of UC patients experienced mucosal healing at W14 and improvement of perianal disease occurred in 96% of CD patients at W54 including 59.1% with complete cessation of drainage. Steroid-sparing effect was markedly present in all patients. Therapy was continued in 83% of patients at the end of the follow-up (89% CD and 64% UC). Trough level of at least 8.9 μg/mL at W6 was best predictive of response at W54 in both CD and UC with a sensitivity of 70.0% and specificity of 74.1% which well corresponds with the results of previous studies on original IFX. Our findings thus suggest that the same association applies also to the biosimilar IFX. Pharmacokinetic properties, immunogenicity and frequency and character of adverse events were similar to those previously observed during treatment with the original IFX.
Conclusions: Biosimilar IFX after one year in naive patients with IBD patients seems to be effective and safe, gaining similar treatment results with no additional safety issues comparing to the originator.