CP-109 Immunogenicity and efficacy of biosimilar of infliximab inflectra in inflammatory bowel disease patients

Background Biosimilars of infliximab have been recently introduced in clinical practice in inflammatory bowel disease (IBD) when compared with rheumatoid arthritis (RA) and ankylosing spondylitis (AS). Based on immunogenicity studies in RA and AS, data were extrapolated to IBD patients. Purpose We aimed to study the imunogenicity of IBD patients (pts) receiving biosimilar inflectra and its impact on clinical management. Material and methods Retrospective cohort analysis of IBD patients on inflectra (April 2014 to April 2015) regarding demographics, epidemiology and blood levels of infliximab and anti-drug antibody (ADA) (before 5th infusion and re-evaluation if treatment strategy modified) after induction (W0, W2, W6) and during maintenance (8/8W; 5 mg/kg). Results N=10; 50% female; switch from adalimumab-9 pts; Crohn’s disease (CD)-8 pts (previous surgery-5 pts; perianal disease-3 pts; CDAI score (n = 8)-102.5 ± 73.19 points; CDEIS score (n = 6)-32.9 ± 12.9 points); ulcerative colitis (UC)=2 pts both with pancolitis (Mayo score -10 and 12 points; Mayo endoscopic score-3). During treatment: IFX monotherapy-2 pts; azathioprine-8 pts; adverse events (AE)-3 pts, 2 stopped. Levels measured (weeks 16–68, n = 13): IFX-10.2 ± 4.9 μg/mL; sub-therapeutic levels ≤7.2 μg/mL in 2 pts both with UC; ADA detectable-4 pts (2 pts-20 ng/mL; 1 pt-25 ng/mL; 1 pt-30 ng/mL; all ANA(-)). Both patients with higher ADA levels were on IFX monotherapy, however with IFX levels within therapeutic range and experienced AE during infusion. Levels measured led to strategy change in 4 pts: 2 stopped (both AE and ADA+); 1 shortened administrations to 4/4w; 1 increased dosage (10 mg/kg). Patients on biosimilar improved: clinically (CDAI-31 ± 24 points; Mayo 1 and 6 points); laboratory parameters (CRP before-12.7 ± 11.8; after-3.1 ± 2.6 mg/L) and endoscopic scores (months 5–9: n = 6; Mayo 1 and 2; CDEIS-21, 4 ± 4.7points; 1 pt went from Rutgeerts 4 to 1 point on inflectra). Conclusion Biosimilar inflectra monotherapy in IBD is associated with ADA presence and occurrence of AE, supporting what is already described in the literature for monotherapy with non-biosimilar infliximab. However, inflectra is effective in patients with CD and UC, even after previous exposure and suboptimal response to adalimumab. References and/or Acknowledgements The authors would like to thank the Laboratory for the Research and Development of Therapeutics Antibodies at the Pharmacy Faculty of the University of Lisbon, for analysis of infliximab trough levels and anti-drug antibodies. No conflict of interest.