PROactive and Early Infliximab Monitoring and OPTimization in Inflammatory Bowel Disease

Infliximab (IFX) is a Food and Drug administration (FDA)-appoved monoclonal antibody medication targeting tumor necrosis factor (TNF) widely used in inflammatory bowel disease (IBD) to treat intestinal inflammation and improve patient's symptoms. Intravenous (iv) IFX is effective to treat hospitalized IBD patients with moderate-to-severe flares who fail iv corticosteroids (CS). However, about one-third of IBD patients do not respond to this medications and a half will loss the response after an initial response. Researchers have shown that most of these phenomena occur due to low IFX concentrations sometimes accompanied by the development of anti-drug antiboides (ADA) againts IFX. Blood concentrations of IFX are widely variable among IBD patients despite receiving the same weight-based dose. Several patient factors including laboratory parameters and severity of intestinal inflammation influence the way an individual's body proccesses and eliminate this type of medications. Dashboard software systems can take into account patient characteristics and IFX concentrations to modelate and facilitate dosing of IFX. By using pharmacokinetics (PK) models specifically developed to facilitate IFX dosing, these softwares can provide and recommend multiple dosing regimes to help the clinicians to select the appropriate dose to achieve target and optimal IFX concentrations. The goal of this clinical trial is to learn if early measuring of IFX blood concentrations and dashboard-guided IFX dose adjustment in Chilean IBD patients starting IFX, increases the proportion of patients with optimal IFX levels and improves patient outcomes. Researchers will measure IFX concentrations before the second (week 2) and third dose (week 6) in a prospectively collected individual patient cohort and this information along with clinical data will be analyzed with a dashboard software system and multiple dosing regime options will be provide to the attending clinicians to facilitate the selection of the next IFX weight-based dose and interval of infusions. This group will be compared with IBD patients with standard of dosing where attending clinicians make the dosing decisions based on clinical parameters. The main goal is to analyze if IBD patients in the dashboard-guided dosing arm achieve a higher proportion of optimal IFX concentrations at week 14 of treatment, develop ADA less frequently and improve clinical outcomes compared with standard dosing group. Participants will be asked to: * Provide clinical data about their disease and other conditions * Provide blood samples at enrollment and before each IFX infusion (IFN) during one year * Maintain regular clinical assessments every 3 months for one year