Background The adjustment of infliximab (IFX) doses is commonly based on subjective data or invasive methods. However, pharmacokinetic monitoring of IFX plasma levels is a currently available tool that has proved to be useful in the optimisation of clinical results.¹

Purpose To analyse the clinical course of acute-phase reactants in patients with inflammatory bowel disease (IBD) treated with IFX, and to evaluate if there is a clinical benefit resulting from applying the pharmacokinetic recommendations in the management of these patients.

Material and methods Retrospective, cross-sectional study carried out in a general hospital. All the determinations of IFX performed during 2017 in patients with IBD were analysed. After analytical determination, the pharmacy service performed a pharmacokinetic study (Bayesian statistics) and recommended a new dosage to the digestive specialist. Identification data of the patients and analytical results (fecal calprotectin and C-reactive protein (CRP)) measured before the monitoring (pre) and 3 months later (post) were collected. In addition, it was evaluated if the digestive specialist followed the pharmacokinetic recommendation (acceptance/rejection).

Results During the study period, the IFX serum levels of 21 patients with IBD were determined. The mean level of fecal calprotectin measured before the extraction of IFX blood levels was 1,257.2 mg/kg and this was reduced to 503.2 mg/kg at 3 months after monitoring (p=0.053). As for CRP, a decrease was also observed, with a CRP value of 7.1 mg/L before monitoring and a CRP value of 3.8 mg/L after 3 months (p=0.035). These data were analysed again, stratifying according to the degree of acceptance of the pharmacist’s recommendations for clinical decision-making (table 1).

Conclusion Both PCR and calprotectin were reduced after 3 months of IFX monitoring. The clinical improvement observed was greater in the group of patients in whom the dose drug was adjusted following the recommendation of the pharmacist. These results support the role of therapeutic IFX monitoring in the optimisation of IBD treatment, according to the evidence published by other authors.

Reference and/or acknowledgements

1. Kelly OB, Donnell SO, Stempak JM, et al. Therapeutic drug monitoring to guide infliximab dose adjustment is associated with better endoscopic outcomes than clinical decision making alone in active inflammatory bowel disease. Inflamm Bowel Dis 2017;23:1202–9.

Reference and/or acknowledgementsNo conflict of interest.