Author information

1 Division of Gastroenterology, Center for Inflammatory Bowel Diseases, Beth Israel Deaconess Medical Center, Harvard Medical School, 330 Brookline Ave., Boston, MA, 02215, USA. kpapamic@bidmc.harvard.edu.

2 Division of Gastroenterology, Perelman School of Medicine, University of Pennsylvania, Philadelphia, PA, USA.

3 Division of Gastroenterology, Center for Inflammatory Bowel Diseases, Beth Israel Deaconess Medical Center, Harvard Medical School, 330 Brookline Ave., Boston, MA, 02215, USA.

Abstract

AIMS: We aimed to investigate drug retention in IBD patients of whom infliximab was optimized to overcome immunogenicity and variables associated with drug retention.

METHODS: This was a retrospective, multicenter study of consecutive IBD patients with antibodies to infliximab (ATI), based on either proactive or reactive therapeutic drug monitoring, who underwent infliximab optimization (increasing dose, shortening interval, adding an immunomodulator, or combination) to overcome immunogenicity from September 2012 to July 2015; they were followed through December 2015. ATI were analyzed using the drug-tolerant Prometheus homogeneous mobility shift assay. Drug retention was defined as no need for drug discontinuation due to SLR or serious adverse event.

RESULTS: Our cohort consisted of 22 patients (Crohn's disease, n = 15). At the end of follow-up [median, (IQR): 17.3 (10.5-32.8) months] 77% (15/22) of patients were still on drug. Univariable Cox proportional hazards regression analysis identified first detectable ATI titer as the only variable associated with drug retention (HR: 0.89; 95% CI: 0.82-0.98, p = 0.016). Receiver-operating characteristic analysis identified an ATI titer < 8.8 U/mL associated with drug retention.

CONCLUSIONS: In real-life clinical practice, optimization of infliximab therapy can prevent drug discontinuation in approximately 3/4 of patients with ATI, especially in those with low titers. Large prospective studies are needed to confirm these data.