Clinical, Radiological and Pharmacokinetic Data of CT-P13 Subcutaneous in Fistulizing Anoperineal Lesions of Crohn’s Disease

Purpose The aim of this study was to evaluate the clinico-radiological remission rate in patients with fistulizing anoperineal lesions of Crohn's disease treated with CT-P13 SC, as well as pharmacokinetic data and treatment persistence rate. Methods We included all consecutive patients seen in the dedicated proctology outpatient clinic between June 1st and July 15th, 2024, for fistulizing anoperineal lesions and treated for at least 3 months with CT-P13 SC. Clinical, radiological and pharmacokinetic data were collected. Results Data from 39 patients were analyzed. The median duration of treatment was 16.1 months. Seventeen patients (43.6%) had received SC formulation from the start. The complete clinical remission rate was 74.4%, significantly higher in patients switched from IV to SC formulation. The deep radiological remission rate was 61.5%. The median infliximab concentration was 22.7 µg/mL. Only the intensified administration protocol impacted infliximab concentration. Immunosuppressants had no impact. The median infliximab concentration was higher in patients in remission (35.9 µg/mL versus 22.4 µg/mL), but without any significant difference. Among patients switched from IV to SC formulation, 86.5% maintained remission. In the overall study population, 89.7% were able to continue treatment, with intensified protocols in 61.5% of patients. Conclusion CT-P13 SC appears to be at least as effective as the IV formulation for fistulizing anoperineal lesions. Switching from IV to SC formulation seems more effective in achieving clinical remission. Despite numerically higher infliximab concentrations in patients in remission, no significant difference could be identified. Switching from IV to SC formulation was associated with maintenance of remission in 86.5% of cases.