Switching intravenous to subcutaneous infliximab was safe and successful during 1-year follow up in Ulcerative Colitis and Crohn patients – a Belgian single center experience

Background:: Subcutaneous (SC) infliximab CT-P13 (IFX) has recently been registered for the treatment of moderate-to-severe inflammatory bowel disease (IBD). The SC route is an attractive option for patients. However, many open questions remain on how to safely switch patients from maintenance IV to SC administration.

Objective: to assess switching from IV to SC IFX therapy in IBD patients through clinical and biochemical evaluation.

Methods: Patients in durable remission on eight-weekly (or six-weekly) IV infliximab and therapeutic IFX trough levels were switched to SC therapy every two weeks. All patients were monitored prospectively every 3 months with patient reported outcomes (PRO), labs including IFX concentrations and faecal calprotectin every 6 months for minimum one-year follow up.

Results: 55 patients (21 UC, 34 CD) agreed to switch to SC therapy. The median follow up in CD patients was 15.5 months, respectively 20 months in UC patients. All patients remained in deep remission according to PRO2, CRP and calprotectin. IFX serum concentrations more than tripled 3 months after the switch (18.31 ± 10.53 μg/mL vs. 4.82 ± 3.06 μg/mL at the start) and remained stable during further follow up. Local pain and injection site reactions both transient were reported in 47% and 42% patients respectively but disappeared in > 50% when injecting in the abdomen or when changing pen to syringe.

Conclusion: Switching UC and Crohn patients in clinical remission and adequate trough levels from maintenance IV tot SC infliximab therapy was successful for at least one year. A proportion of patients experienced pain and or injection site reactions.

Keywords: infliximab, CT-P13, subcutaneous therapy, Crohn’s disease, ulcerative colitis.