Proactive Infliximab Optimization Using a Pharmacokinetic Dashboard Versus Standard of Care in Patients With Inflammatory Bowel Disease: The OPTIMIZE Trial

Inflammatory bowel disease (IBD), namely Crohn's disease (CD) and ulcerative colitis (UC) are life-long chronic diseases characterized by transmural inflammation of the intestine. CD and UC are global diseases in the 21st century with increasing incidence in newly industrialized countries. One of the most effective therapies to treat patients with moderate to severe disease is the antitumor necrosis factor (TNF) agent infliximab (IFX) either as monotherapy or as a combination therapy with an immunomodulator (IMM), such as azathioprine or methotrexate (MTX).

Although more effective, combination therapy is associated with more serious adverse events, such as serious opportunistic infections and cancers, as well as potential treatment adherence issues. Consequently, many patients and physicians choose to use IFX alone as safety is often prioritized over efficacy. Unfortunately, up to 30% of patients do not respond to induction therapy, and up to 50% of initial responders lose response over time. It is only if patients lose response that physicians check blood IFX concentrations (i.e., reactive therapeutic drug monitoring [TDM]), or empirically increase IFX dose. Reactive TDM helps to explain and better manage these patients with lack or loss of response to IFX. In many cases, the lack or LOR is due to low drug concentrations with or without development of antibodies to IFX (ATI). Unfortunately, reactive TDM or empiric dose escalation is often too late for patients who do not either respond to IFX induction therapy or lose response during maintenance. This reactive approach results in many patients losing IFX as a therapeutic option.

Preliminary data show that proactive IFX optimization to achieve a threshold drug concentration during maintenance therapy (even if the patient is asymptomatic) compared to empiric dose escalation and/or reactive TDM is associated with better long-term outcomes including longer drug persistence, reduced risk of relapse, and fewer hospitalizations and surgeries. IFX dosing by weight only (i.e., mg/kg) may not be adequate for many patients as interindividual variability in drug clearance and other factors affecting IFX concentrations and PK are often not accounted for. Dosing calculators take into account all of these individual factors and improve the precision of dosing towards better personalized medicine. These systems have already been validated, and personalized dosing has shown clinical benefit in patients with IBD.

This is a randomized, controlled, multicenter, open-label study that plans to enroll 196 participants with inflammatory bowel disease. All eligible participants will be randomly assigned in a 1:1 ratio to receive either IFX monotherapy with proactive TDM or SOC IFX therapy, with or without concomitant IMM therapy, and empiric dose optimization or reactive TDM, at the discretion of the investigator.