P736 Utility of infliximab serum concentration in inflammatory bowel disease treatment in real world practice at Hospital Universitario de Canarias

M. Carrillo Palau1, I. Alonso-Abreu1, L. Ramos-Lopez1, G.N. Fernando2, N. Hernandez Alvarez-Buylla1, A. Hernandez-Perez1, S. Medina-Chico1, E. Quintero1

1Hospital Universitario De Canarias, Department of Digestive Service- Department of Gastroenterology, Santa Cruz De Tenerife, Spain, 2Hospital Universitario De Canarias, Department of Pharmacy, Santa Cruz De Tenerife, Spain

Background

Anti-TNF drugs are effective treatments for the management of inflammatory bowel disease (IBD) but treatment failure is common. The aim of this study was to investigate the association between inflammatory biomarkers, serum concentrations of IFX and antiIFX antibody concentration during induction and maintenance treatment and to investigate the association with disease activity and response to treatment in our patients from 2017 to 2019.

Methods

Retrospective observational study. We enrolled patients receiving IFX from March 2017 until March 2019. Demographic data, disease characteristics, previous medical treatments and surgeries were recorded. Clinical Activity Index (Harvey Index and Parcial Mayo Score) and CRP, faecal calprotectine (FC) and endoscopy or radiological activity were recorded at baseline, and at 6, 12 and 24 months of treatment. IFX serum concentrations and anti-IFX antibody concentration were measured at the end of induction (week 8) and during follow-up (6, 12 and 24 months).

Results

One hundred and eighty-one IBD patients were treated during the study period, and 175 patients were included: 128 (73.1%) Crohn’s disease (CD), 46 (26.3%) ulcerative colitis (UC) and 1 (0.6%) indeterminated colitis (IC). 95 male, 85 female, mean age 45 years (±15); 93% were naive to IFX. 73.6% started IFX combined with inmunomodulator treatment. At week 0, 80% had an active disease (Global Physician Assessment), 58.8% had CRP >5 μg/dl and 62% had FC > 150 mg/kg. At 12 months, 126 patients continued under IFX, and 68% had an stable disease and 44% were intensified. Thirty-six per cent had CRP > 5 μg/dl and 37% FC>150 mg/kg. At 24 months, 90 patients continued with IFX, from which 80% were stable and 43% were intensified.38% had CRP >5 μg/dl and 26% FC >150 mg/kg. Patients with post-induction (week 8) serum IFX concentration >7 μg/ml had more stable disease (p: 0.04) at that moment and IFX serum concentration > 3 μg/ml at 18 months was corelationated with no inflammation at endoscopy or radiology (p: 0.025). In the multivariate analysis stenosant phenotype and CRP < 5 mg/dl at 6 months were relationated with early stop of IFX treatment (<1 year).

Conclusion

Our study shows that IFX levels >7 μg/ml correlates with a better clinical response. Disease phenotype and inflammatory parameters could influence in long time maintenance treatment. Drug-level monitoring and measurement of baseline inflammatory parameters may improve the management of IBD.