4CPS-064 Pharmacokinetic monitoring of subcutaneous infliximab in patients with inflammatory bowel disease
Year: 2025
Type: conference-paper
Study design: Observational Study
Abstract: Background and Importance Subcutaneous infliximab(SC-IFX) shows stable drug concentrations over time in patients with inflammatory bowel disease(IBD). Establishing an optimal cut-off would help ensure treatment effectiveness and safety. Aim and Objectives To analyse the variability of trough concentration(Cmin) of SC-IFX and establishing a cut-off to achieve clinical response(CR), biochemical remission(RemBq) and clinical remission(RemC) during the maintenance phase in IBD patients. Material and Methods Ambispective, observational study involving IBD patients with IFX Cmin starting SC-IFLX treatment between January 2020-June 2024. Clinical data were extracted from the Abucasis/MDIS programme. Variables analysed were sex, age, weight, diagnosis(Crohn disease(CD)/Ulcerative colitis(UC), pharmacotherapeutic data(Cmin, previous biological therapy), biochemical parameters(albumin, faecal calprotectin(FCP), C-reactive protein(CRP)) and clinical score(UC:Partial-Mayo Score(MS)/CD:Harvey-Bradshaw index(HB)) at each time point. Study objectives were defined as: Clinical Response(CR: maintaining a clinical score equal to/lower than the baseline); Biochemical Remission(RemBq: FCP<250μg/g and CRP<5mg/L); and Clinical Remission(RemC: HB<5 and MS<2). As a limitation due to the ambispective design, the available patient’s drug levels were variable at 3rd, 6th and 12th months(n=52,n=41,n=40). SC-IFLX Cmin was determined using a chemiluminescence assay(Theradiag). The results were expressed as percentage, and median[interquartile range(IQR)]. The Friedman test assessed differences between Cmin, and ROC curve analysis determined the optimal cut-off to maximise sensitivity(S) and specificity(E), using R v.4.3.3 for data analysis. Results Samples from 52 patients(n=42;CD) were analysed: 27 were male(51.9%). The median age and weight were 45.0 years[34.0–56.0] and 70.0 kg[62.0–83.0], respectively. A total of 8 patients had prior treatment with a biological therapy other than infliximab. Cmin at 3, 6, and 12 months were 15.1μg/mL[IQR:10.4–19.4], 13.7μg/mL[IQR:10.0–16.7], and 14.3μg/mL[IQR:10.2–17.4],p=0.226, respectively. Analytic parameters in the three visits were: albumin (4.4[IQR:4.2–4.6]; 4.4[IQR:4.2–4.5]; 4.4[IQR:4.3–4.7]g/dL), CRP(1.3[IQR:1.0–3.3]; 1.5[IQR:1.0–3.1]; 1.4[IQR:1.0–3.0]mg/L) and FCP(58.0[IQR:30.5–199.4]; 105.2[IQR:37.4 −265.1]; 75.6[IQR:32.3–316.2]μg/g, respectively. SC-IFX cut-off for CR at the 3rd and 12th months was 13.5μg/mL (AUC=0.90 [95% CI:0.82–0.98],p=0.024,S=0.83,E=0.87) and 13.7μg/mL (AUC=0.77 [95% CI:0.61–0.93],p=0.02,S=0.68,E=0.88), respectively. For RemBq, the cut-off at the 3rd month was 16.8μg/mL(AUC=0.76 [95% CI:0.63–0.90],p=0.07,S=0.53,E=0.92). No statistically significant differences were found for other study objectives. Conclusion and Relevance Based on the results, SC-IFLX Cmin remained stable over the follow-up period. A cut-off for CR was identified at 13.5μg/mL and 13.7μg/mL, and a cut-off of 16.8μg/mL for RemBq. However, further studies are required to confirm these findings and establish an optimal cut-off that ensures favourable clinical outcomes. References and/or Acknowledgements Conflict of Interest No conflict of interest
Institution: Hospital Universitari i Politècnic La Fe
Language: English
Topic: Inflammatory Bowel Disease
Subfield: Genetics
Domain: Life Sciences
Open Access status: gold
OpenAlex ID: W4408376307