Does calprotectin guide the treatment course for Crohn's disease?

From the Guidelines

Calprotectin is a valuable tool in guiding the treatment course for Crohn's disease, as it helps clinicians monitor intestinal inflammation and make informed decisions about treatment adjustments. According to the 2023 AGA clinical practice guideline on the role of biomarkers for the management of Crohn's disease 1, a fecal calprotectin level <150 mg/g and normal CRP can rule out active inflammation in patients with CD in symptomatic remission, potentially avoiding the need for endoscopic evaluation. In contrast, elevated biomarkers in this setting merit confirmation with endoscopy before treatment adjustment. The guideline suggests that in patients with CD with moderate to severe symptoms, elevated fecal calprotectin or serum CRP suggests endoscopic activity, precluding routine endoscopic assessment for disease activity. Key points to consider when using calprotectin to guide treatment include:

• Fecal calprotectin levels can help identify patients with active inflammation, even in the absence of symptoms
• Elevated calprotectin levels (>150 mg/g) may indicate the need for treatment adjustment, such as intensifying therapy or adding an immunomodulator
• Normal calprotectin levels (<150 mg/g) can support maintaining current therapy or considering dose de-escalation
• Calprotectin should be interpreted alongside clinical symptoms, as some patients may have elevated levels without symptoms or normal levels despite symptoms. Overall, the use of calprotectin as a biomarker can help clinicians make more informed treatment decisions and improve patient outcomes in Crohn's disease, as supported by the recent guideline 1.

From the Research

Calprotectin as a Guide for Treatment Course in Crohn's Disease

• Calprotectin is a biomarker that has been studied for its potential to guide treatment courses in Crohn's disease 2, 3, 4, 5, 6
• Research has shown that fecal calprotectin can be used to characterize the heterogeneity of Crohn's disease and predict disease trajectories 2
• A study found that calprotectin levels were significantly associated with smoking, upper gastrointestinal involvement, and early biologic therapy in patients with Crohn's disease 2
• Fecal calprotectin has also been shown to have diagnostic accuracy for the detection of small-bowel Crohn's disease, with a negative predictive value of 91.8% for a cut-off of 50 μg/g 3

Predicting Treatment Outcomes with Calprotectin

• Calprotectin levels at Week 6 have been found to be predictive of long-term endoscopic healing in Crohn's disease, with a cut-off of <250 mg/kg demonstrating fair accuracy 6
• A study found that patients with a Week 6 fecal calprotectin <250 mg/kg had 3.48 times increased odds of Week 52 endoscopic remission 6
• Calprotectin levels have also been linked to azathioprine metabolite concentrations in Crohn's disease, with significantly lower calprotectin levels observed in patients with 6-thioguanine nucleotides concentrations within a predefined range 5

Clinical Applications of Calprotectin

• Calprotectin may be a useful biomarker for guiding treatment decisions in Crohn's disease, particularly in predicting response to therapy and monitoring disease activity 4, 5, 6
• Further research is needed to fully understand the clinical applications of calprotectin in Crohn's disease and to establish its role in treatment algorithms 2, 3, 4, 5, 6