P530 Ultra-proactive therapeutic drug monitoring incorporating infliximab point-of-care testing with ad hoc dose adjustment reduces C-reactive protein levels in patients with IBD during infliximab maintenance treatment
P. Bossuyt*1,2, E. Hoefkens2, I. Geerts3, F. Verbiest4, E. Vermeulen3, A. Van Olmen2, L. Pouillon2
1University Hospitals Leuven, Catholic University of Leuven, Department of Gastroenterology and Hepatology, Leuven, Belgium, 2Imelda General Hospital, Department of Gastroenterology, Bonheiden, Belgium, 3Imelda General Hospital, Department of Laboratory Medicine, Bonheiden, Belgium, 4Imelda General Hospital, Central Hospital Pharmacy, Bonheiden, Belgium
Therapeutic drug monitoring (TDM) of infliximab (IFX) improves patient outcomes and is cost-effective. The short turnaround time of point-of-care testing (POCT) allows ad hoc dose adjustment. We aimed to determine the feasibility and pilot effectiveness of an ultra-proactive TDM algorithm including POCT of IFX in patients with inflammatory bowel disease (IBD).
All IBD patients with maintenance IFX treatment at our referral IBD clinic were prospectively included between June and August 2018. An ultra-proactive IFX TDM algorithm was applied as follows. All patients had an ELISA trough level (TL) measurement at baseline, of which the result determined the follow-up pathway: (A) TL between 3–7 μg/ml: continuation at same dose and interval; (B) TL >7 μg/ml: interval prolongation allowed; (C) TL <3 μg/ml: interval shortening with minimum 2 weeks, with the next IFX TL measured using a POCT. (i) If the POCT showed an IFX TL <3 μg/ml, dose was optimised ad hoc using a linear dosing formula (Dosen = (TLtarget * Dosen−1) / TLmeasured), followed by a new POCT test at next visit with the same interval. (ii) If the POCT showed an IFX TL ≥3 μg/ml, no additional dose was given and routine TL testing with ELISA was retaken at next visit. Physician’s global assessment, C-reactive protein (CRP), haemoglobin and albumin levels were sequentially evaluated according to standard of care.
In total, 115 patients were included (Crohn’s disease/ulcerative colitis/IBDU
Ultra-proactive TDM based on a strict algorithm including POCT and ad hoc dose adjustment is feasible and significantly lowers CRP levels in IBD patients treated with maintenance IFX. Less than 10% of patients need POCT over time.