Evaluating Efficacy, Safety, and Pharmacokinetics After Switching From Infliximab Originator to Biosimilar CT-P13: Experience From a Large Tertiary Referral Center.

Background: The use of infliximab biosimilar CT-P13 has increased in patients with inflammatory bowel disease. Nevertheless, doubts about switching from infliximab originator to biosimilar still exist among patients and health care professionals.

Methods: Our tertiary referral center underwent a mandatory switch from infliximab originator to CT-P13 in 2017. We investigated pharmacokinetics, efficacy, and safety of this switch. The primary endpoint was infliximab discontinuation within 6 months of switching. Secondary endpoints included loss of clinical remission, need for treatment optimization, adverse events, evolution of patient-reported outcome, C-reactive protein, infliximab trough levels, and antidrug-antibodies.

Results: A total of 361 patients (54.0% male, 70.0% Crohn's disease, 55.6% in clinical remission) were enrolled. Infliximab discontinuation within 6 months was observed in 4%. Loss of clinical remission, adverse events, and antidrug-antibodies were identified in only 2.0%, 2.2%, and 1.1% of patients, respectively. C-reactive protein concentrations and infliximab trough levels remained stable. Independent factors associated with remission at 6 months were lower PRO2 at switch (HR 6.024; 95% CI, 4.878-8.000; P < 0.0001) and higher hemoglobin levels (HR 1.383; 95% CI, 1.044-2.299; P = 0.018).

Conclusions: Switching from infliximab originator to CT-P13 was not associated with an increased risk of treatment discontinuation, loss of clinical remission, or adverse events. No significant changes in infliximab trough levels or immunogenicity could be identified.