NP-010 Clinical and pharmacokinetic results after the switch to infliximab biosimilar in inflammatory bowel disease: 2 years of real-life experience

Background Debate on the use of biosimilars focuses on the therapeutic efficacy and safety of switching between biosimilars and their reference products. Purpose To determine the clinical results and pharmacokinetic behaviour of switching from originator infliximab to biosimilar in patients with inflammatory bowel disease (IBD) over 2 years. Materials and methods Prospective, longitudinal study (April 2017–March 2019). Patients with ulcerative colitis (UC) or Crohn’s disease (CD) treated with originator infliximab (Remicade) and changed to biosimilar (CT-P13) were included. The following outcome variables were defined: Clinical Remission (CR)= Harvey Bradshaw index Infliximab serum concentrations were determined by ELISA and pharmacokinetic parameters (volume of distribution (Vd) and clearance (CL)) were estimated by Bayesian population pharmacokinetics analysis. Evaluation of variables was performed in four temporal sections: prior to the switch, immediately after, and again 8 months and 2 years after. ANOVA test was used to compare pharmacokinetic parameters means and the percentage of patients who reached the outcome variables in the different temporal sections was calculated. Results 42 patients (55% women) were included, with a median [range] age of 42 [18-70] years, 10 diagnosed of UC and 32 of CD. Prior to the switch, 93% of the patients presented CR and ER, and 95% BR. These results were identical immediately after switching. Eight months after the switch, 93% of the patients presented CR and 88% ER and BR. At the end of the two years’ follow-up, 97% presented CR and 92% ER and BR. Regarding pharmacokinetic behaviour, there were no significant differences between the average values of CL estimated in the different sections, which were: 0.393 L/d; 0.392 L/d; 0,395 L/d and 0,390 L/d (p=0.91), nor among the Vd, whose results were: 5.25 L; 5.25 L; 5.24 L and 5.28 L (p=0.93), respectively. Conclusion After switching from infliximab originator to biosimilar in a real cohort of IBD patients, no changes in clinical outcomes or pharmacokinetic behaviour were observed over 2 years, which supports the switch in clinical practice.