P639 Switching from originator-infliximab to biosimilar-Infliximab in IBD-patients does not lead to significant changes in infliximab trough levels
Eberl A.*1,2, Huoponen S.2, Pahikkala T.3, Arkkila P.1,2, Blom M.2, Sipponen T.1,2
1Helsinki University Central Hospital - Meilahti Hospital, Department of Gastroenterology, Helsinki, Finland 2University of Helsinki, Biomedicum 2C, Helsinki, Finland 3Unversity of Turku, Department of Information Technology, Turku, Finland
Clinical use of biosimilar-infliximab (CT-P13) in inflammatory bowel diseases (IBDs) is based on extrapolation of indication from clinical studies performed in rheumatoid arthritis and ankylosing spondylitis. Only few data exist of behavior of infliximab trough level (TL) and anti-drug antibodies (ADA) during switching. The objective of this study was to evaluate the changes in TL and ADA after switching from originator-infliximab to biosimilar one during IBD maintenance therapy.
In this single-center observational study, all IBD patients receiving maintenance infliximab therapy were switched to biosimilar-infliximab. Serum samples for measurements of TL and ADA were taken before the last originator-infliximab infusion (baseline samples) and before the third biosimilar-infliximab infusion (follow-up samples). TL and ADA were measured by ELISA Data of laboratory values, demographic data, clinical disease activity (HBI or partial Mayo score) and concomitant medication were collected from patients records.
Baseline TL and ADA were available of 78 patients (45 males, 37 UC, 38 CD and 3 IBDU). The baseline low or high TL led to change in infliximab dosing in 16 patients and these were excluded from final analysis. No significant changes in TL occurred after switching (p=0.05): The mean baseline TL was 6.55 mg/l (SD 3.53) and follow-up TL was 5.73 mg/l (SD 3.21). ADAs were detectable in one sample at baseline. Two patients developed ADAs after switching (titer 12 AU/ml and 35 AU/ml, respectively). Mean baseline partial Mayo score was 1.19 (SD 1.73) and mean follow up Mayo score 0.77 (SD 1.26), mean baseline HBI was 1.25 (SD 2.31) and mean follow up HBI 1.19 (SD 2.25). The disease activity during switching neither in UC or in CD showed no statistical difference, p=0.07 and p=0.89.
These data suggest that switching from originator-infliximab to biosimilar-infliximab does not cause any statistically significant differences in infliximab trough concentrations. No safety concerns occurred during 16 weeks following switching.