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P409 Non-medical reverse switch between the originator infliximab and its biosimilar in patients with inflammatory bowel disease: clinical outcomes and therapeutic drug monitoring

L. Gonczi*1, A. Ilias1, K. Szanto2, Z. Kurti1, P. A. Golovics3, K. Farkas2, E. Schafer3, Z. Szepes2, B. Szalay4, A. Vincze5, T. Szamosi3, T. Molnar2, P. Lakatos6

1Semmelweis University, First Department of Internal Medicine, Budapest, Hungary, 2University of Szeged, First Department of Medicine, Szeged, Hungary, 3Military Hospital – State Health Centre, Department of Gastroenterology, Budapest, Hungary, 4Semmelweis University, Department of Laboratory Medicine, Budapest, Hungary, 5University of Pecs, First Department of Medicine, Pecs, Hungary, 6McGill University Health Center, Division of Gastroenterology, Montreal, Canada

Background

Switching from the originator to a biosimilar infliximab (IFX) in patients with inflammatory bowel disease (IBD) has proven to be successful, although clinical evidence is lacking on reverse and/or multiple switching. The aim of the present study was to evaluate medium-term drug sustainability, safety and immunogenicity profile of reverse switching from a biosimilar to the originator IFX in a consecutive multi-centre real-life cohort.

Methods

We performed a prospective observational study of 174 consecutive patients with IBD (136 with Crohn’s disease [CD] and 38 with ulcerative colitis [UC]) who were switched from the biosimilar infliximab CT-P13 to the originator Remicade during maintenance therapy. Previous exposure to the originator was 8% (n = 14). In September 2017, a non-medical reverse switch took place in all Hungarian patients from the biosimilar to the originator infliximab due to change in reimbursement policies. We collected clinical and biochemical information from patients at baseline (time of the switch) and 8, 16 and 24 weeks thereafter. Serum drug trough levels and anti-drug antibodies were measured at baseline and Week 16.

Results

Complicated disease behaviour and perianal manifestation was present in 39.7% and 48.5% of CD patients. 54.1% of UC patients had extensive colitis. Previous exposure to the originator was 8.0% (n = 14). There was no significant difference between the proportion of patients in clinical remission (based on Crohn’s disease Activity Index <150 points or no fistula drainage; partial Mayo score <3) at Week 8 before switch, at switch/baseline and at Week 16 and 24 (CD: 82.6/80.6/77.5/76.3%, p = 0.60; UC: 82.9/81.6/83.7/84.8%, p = 0.98). In all IBD patients, mean serum IFX trough levels were 5.33 µg/ml (SD: 4.70) at baseline and 5.69 µg/ml (SD: 4.94) at week 16 (p = 0.71). No significant differences were observed in anti-drug antibody (ADA) formation either (overall ADA positivity: 16.2% vs. 16.9% at baseline/week16; p = 0.87). Four infusion reactions occurred up to Week 24 follow-up. There was no difference in clinical outcomes or TDM between patients with or without previous exposure to the originator.

Conclusion

This is the first real-life cohort on mandatory reversed switch from biosimilar to originator IFX in IBD patients. No significant changes were observed in trough levels or ADA status after the reversed switch in parallel with good medium-term drug sustainability. No new safety signals were detected.