Detection of anti-infliximab antibodies in Slovak IBD patients and its costs saving effect.

OBJECTIVE: Management chronic inflammatory bowel disease (IBD) patients is associated with diagnosis, targeted treatment and and individual approach. There is a group of patients which loss the response to the biologic treatment caused by insufficient levels of biologics or positive antibodies against these drugs. This study was aimed to determine the prevalence of patients with positive antibodies against the biological treatment and the costs saving probabilities of the antibodies detection during the treatment. STUDY DESIGN: This retrospective study was based on examination of 183 IBD patients' sera (72 with Crohn's disease (CD) and 111 ulcerative colitis (UC)) treated with infiliximab. METHODS: Circulating serum infliximab concentrations and anti-infliximab antibodies (ATI) were quantified by ELISA methods. Costs associated with the treatment were analysed from the data of General Health Insurance Company, Slovakia. RESULTS: The average infliximab concentrations in groups of CD were 2.9 µg/mL, 38.9% of samples had a concentration ≤1 µg/mL. Group with UC had average infliximab levels of 3.19 µg/mL, 32.4% bellow ≤1 µg/mL. Positive ATI levels were detected in 52 patients, in 28 patients with CD (38.8%) and 24 patients with UC (21.6%). The average values of the antibodies were 387.75 U/ml in CD and 391.94 U/ml in UC group. More than 28% IBD patients were positive for ATI. After application of the results to the database of all IBD patients, finishing of the treatment with ATI could lead (after considering the ATI quantification costs) to possible annual savings of more than €2 million in Slovakian health-care system. CONCLUSIONS: Monitoring of infliximab and antibodies against infliximab and anti-TNF-α biologics may help optimize treatment strategies and costs for biological treatment.