title: The Utility of Infliximab Therapeutic Drug Monitoring among Patients with Inflammatory Bowel Disease and Concerns for Loss of Response: A Retrospective Analysis of a Real-World Experience.
abstract: Background. Infliximab (IFX) therapeutic drug monitoring (TDM) allows for objective decision making in patients with inflammatory bowel disease (IBD) and loss of response. Questions remain about whether IFX TDM improves outcomes.Methods. Patients with IBD who had IFX TDM due to concerns for loss of response were considered for inclusion. Serum IFX trough concentration and anti-drug antibody (ADA) concentrations were measured. Patients were grouped by TDM results: group 1, low IFX/high ADA; group 2, low IFX/low ADA; group 3, therapeutic IFX. Changes in management were analyzed according to groupings; remission rates were assessed at 6 months.Results. 71 patients were included of whom 37% underwent an appropriate change in therapy. Groups 1 (67%) and 2 (83%) had high adherence compared to only 9% in group 3. At 6 months, 57% had achieved remission. More patients who underwent an appropriate change in therapy achieved remission, though this did not reach statistical significance (69% versus 49%;P= 0.098).Conclusions. A trend towards increased remission rates was associated with appropriate changes in management following TDM results. Many patients with therapeutic IFX concentrations did not undergo an appropriate change in management, potentially reflecting a lack of available out-of-class options at the time of TDM or due to uncertainty of the meaning of the reported therapeutic range.
authors.affiliation: St. Paul's Hospital, Department of Medicine, Division of Gastroenterology, University of British Columbia, Vancouver, BC, Canada.
authors.forename: Robert A
authors.identifier: 0000-0001-8587-234X
authors.initials: RA
authors.lastname: Mitchell
authors.affiliation: St. Paul's Hospital, Department of Medicine, Division of Gastroenterology, University of British Columbia, Vancouver, BC, Canada.
authors.forename: Constantin
authors.initials: C
authors.lastname: Shuster
authors.affiliation: St. Paul's Hospital, Department of Medicine, Division of Gastroenterology, University of British Columbia, Vancouver, BC, Canada.
authors.forename: Neal
authors.identifier: 0000-0002-4536-0515
authors.initials: N
authors.lastname: Shahidi
authors.affiliation: St. Paul's Hospital, Department of Medicine, Division of Gastroenterology, University of British Columbia, Vancouver, BC, Canada.
authors.forename: Cherry
authors.identifier: 0000-0001-9353-7381
authors.initials: C
authors.lastname: Galorport
authors.affiliation: Department of Pathology and Laboratory Medicine, University of British Columbia, Vancouver, BC, Canada.
authors.forename: Mari L
authors.initials: ML
authors.lastname: DeMarco
authors.affiliation: St. Paul's Hospital, Department of Medicine, Division of Gastroenterology, University of British Columbia, Vancouver, BC, Canada.
authors.forename: Gregory
authors.initials: G
authors.lastname: Rosenfeld
authors.affiliation: St. Paul's Hospital, Department of Medicine, Division of Gastroenterology, University of British Columbia, Vancouver, BC, Canada.
authors.forename: Robert A
authors.identifier: 0000-0002-9018-4522
authors.initials: RA
authors.lastname: Enns
authors.affiliation: St. Paul's Hospital, Department of Medicine, Division of Gastroenterology, University of British Columbia, Vancouver, BC, Canada.
authors.forename: Brian
authors.identifier: 0000-0003-4740-8209
authors.initials: B
authors.lastname: Bressler
mesh_terms: D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D000906:Antibodies / Q000097:blood / Q000276:immunology; D054316:Biomarkers, Pharmacological / Q000097:blood; D016903:Drug Monitoring / Q000379:methods*; D005260:Female; D005765:Gastrointestinal Agents / Q000008:administration & dosage / Q000097:blood* / Q000276:immunology; D006801:Humans; D015212:Inflammatory Bowel Diseases / Q000097:blood / Q000188:drug therapy*; D000069285:Infliximab / Q000008:administration & dosage / Q000097:blood* / Q000276:immunology; D008297:Male; D008875:Middle Aged; D012074:Remission Induction; D012189:Retrospective Studies; D017211:Treatment Failure; D055815:Young Adult
chemical_list: D000906:Antibodies; D054316:Biomarkers, Pharmacological; D005765:Gastrointestinal Agents; D000069285:Infliximab