Predictive value of infliximab trough levels in maintenance therapy for 5-year sustained clinical remission in patients with inflammatory bowel disease.

Background: Despite long-term use of infliximab (IFX) in IBD treatment, its optimized use is unclear due to its complicated pharmacokinetics/dynamics. Hence, the predictive value of IFX trough levels (TL) is important in treatment management.

Methods: We performed a prospective, cross-sectional, observational study with 74 IBD patients treated with IFX (mean 9.1 years, SD ± 3). TL was measured during maintenance therapy, in which maintenance of remission was followed for 5 years.

Results:  TL > 3 µg/ml during maintenance therapy was a significant predictor of clinical remission in 5 years in UC patients (82 % vs 62 %, p 3 µg/ml during maintenance therapy in a cohort of IBD patients (p = 0.05). Deviations in percentage of remission and fraction of relapses in TL categories were insignificant in a cohort of CD patients (85 % vs 74 %, p > 0.05).

Conclusions:  TL > 3 µg/ml during maintenance therapy is a strong predictor of sustained clinical remission for 5 years in UC patients. The use of combination therapy with AZA, due to its significant association with high TL, may have a practical benefit in achieving better clinical outcomes in UC patients (Tab. 2, Fig. 10, Ref. 20).