Applying Biomarkers in Treat-to-target Approach for IBD

Abstract

Purpose of review: The treatment of inflammatory bowel disease (IBD) has evolved significantly over time based on "treat-to-target", an approach which uses sequential objective makers to monitor response to therapy with the ultimate goal of achieving endoscopic healing. Biomarkers, including C-reactive protein and fecal calprotectin, are an important noninvasive intermediate step in this treatment approach as well as in routine monitoring of disease activity. While widely utilized, there is significant variability and some uncertainty in biomarker implementation; this review summarizes evidence for the use of biomarkers in IBD.

Recent findings: The Selecting Therapeutic Targets in Inflammatory Bowel Disease (STRIDE) update in combination with the 2023 American Gastroenterological Association (AGA) guidelines on the role of biomarkers in the management of both Crohn's disease and ulcerative colitis have offered significant new guidance for those who manage IBD. Biomarkers offer important insight into disease activity and can be used to track progress toward deeper levels of remission in IBD.

Keywords: Biomarkers; C-reactive protein; Fecal calprotectin; Treat-to-target.

Fig. 1

Ulcerative colitis and Crohn’s disease treatment recommendations in setting of elevated biomarkers based on clinical presentation. In patients with calprotectin over 150 μg/g or CRP > 5 mg/L, assess symptom status. Those who are asymptomatic may require endoscopic assessment for further evaluation or short interval repeat biomarkers. Those with mild symptoms typically require endoscopic assessment (see second bullet point in special circumstances). Those with moderate to severe symptoms, may undergo therapy adjustment (i.e. check drug levels and adjust) or endoscopic evaluation if options for changes in therapy are limited or endoscopy is needed for other reasons (i.e. rule out CMV). Pouchitis recommendations are discussed in the text. Abbreviations: CRP: C reactive protein, FC: fecal calprotectin, CMV: cytomegalovirus