title: Proactive therapeutic concentration monitoring of infliximab may improve outcomes for patients with inflammatory bowel disease: results from a pilot observational study.
abstract: BACKGROUND
  Infliximab (IFX) is effective in the treatment of inflammatory bowel disease; however, the effect is often not durable. It is unknown if proactive therapeutic concentration monitoring (TCM) of IFX improves outcomes.
  
  
  METHODS
  This is a retrospective observational study examining the use of proactive TCM and titration of IFX to a target concentration for patients with inflammatory bowel disease in clinical remission at a tertiary care center. The primary aim was to describe the clinical course of patients who had proactive TCM. A secondary analysis was done to assess if this strategy was superior to the standard of care.
  
  
  RESULTS
  Forty-eight patients were identified as having proactive TCM. Fifteen percent had an initial undetectable trough concentration. Twenty-five percent (12 of 48) of patients escalated IFX after the first proactive TCM while 15% (7 of 48) of patients de-escalated IFX therapy over the study period. A control group of 78 patients was identified. Patients who had proactive TCM had a greater probability of remaining on IFX than controls (hazard ratio, 0.3; 95% confidence interval, 0.1-0.6; log rank test; P = 0.0006). The probability of remaining on IFX was greatest for patients who achieved a trough concentration >5 μg/mL (hazard ratio, 0.03; 95% confidence interval, 0.01-0.1; P < 0.0001 versus trough <5 μg/mL). Fewer patients in the proactive TCM group stopped IFX (10% versus 31%, P = 0.009).
  
  
  CONCLUSIONS
  In this pilot observational study, proactive TCM of IFX frequently identified patients with low or undetectable trough concentrations and resulted in a greater probability of remaining on IFX.
authors.affiliation: *Center for Inflammatory Bowel Diseases, Division of Gastroenterology, Beth-Israel Deaconess Medical Center, Harvard Medical School, Boston, Massachusetts; and †Division of Gastroenterology, University of California San Diego, La Jolla, California.
authors.forename: Byron P
authors.initials: BP
authors.lastname: Vaughn
authors.forename: Manuel
authors.initials: M
authors.lastname: Martinez-Vazquez
authors.forename: Vilas R
authors.initials: VR
authors.lastname: Patwardhan
authors.forename: Alan C
authors.initials: AC
authors.lastname: Moss
authors.forename: William J
authors.initials: WJ
authors.lastname: Sandborn
authors.forename: Adam S
authors.initials: AS
authors.lastname: Cheifetz
mesh_terms: D000328:Adult; D000911:Antibodies, Monoclonal / Q000493:pharmacokinetics / Q000627:therapeutic use*; D016022:Case-Control Studies; D016903:Drug Monitoring; D005260:Female; D005500:Follow-Up Studies; D005765:Gastrointestinal Agents / Q000493:pharmacokinetics / Q000627:therapeutic use*; D006801:Humans; D015212:Inflammatory Bowel Diseases / Q000097:blood / Q000188:drug therapy* / Q000276:immunology; D000069285:Infliximab; D008297:Male; D008875:Middle Aged; D010865:Pilot Projects; D011379:Prognosis; D012189:Retrospective Studies; D014018:Tissue Distribution
chemical_list: D000911:Antibodies, Monoclonal; D005765:Gastrointestinal Agents; D000069285:Infliximab