P611 Serological biomarkers of type VI and XXII collagen formation predict and monitor infliximab treatment response in patients with Crohn’s disease
Authors: Sorokina Alexdóttir M , Bourgonje A R , Karsdal M A , Bay-Jensen A C , Pehrsson M , Loveikyte R , van Dullemen H M , Visschedijk M C , Festen E A M , Weersma R K , Faber K N , Dijkstra G , Mortensen J H 
Published: January 2022

Abstract

Background
Crohn’s disease (CD) is a chronic inflammatory disease of the gastrointestinal (GI) tract characterized by excessive protease activity and extracellular matrix (ECM) remodeling. Although biologics such as TNF-α antibodies have improved the management of disease, up to 30–50% of patients still experience non-response to treatment. Biomarkers may be useful to improve therapeutic decision-making and monitor treatment response, thereby optimizing biological therapy and decreasing the risk of surgical intervention. This study assessed whether serological biomarkers of ECM turnover could monitor or predict response to TNF-α-antagonists in patients with and without surgical history.

Methods
Using protein fingerprint technology, serum biomarkers of type VI (PRO-C6) and XXII (PRO-C22) collagen formation were measured in 63 patients with CD undergoing infliximab (IFX) induction therapy. Disease activity was defined by a composite of the Harvey-Bradshaw Index (HBI) and physician’s global assessments (PGA). Response to treatment was defined as steroid-free remission (HBI&lt;5) at week 14. Patients were stratified according to history of prior surgery. Patients with history of prior surgery (n=18) were 10 responders and 8 non-responders. Patients without history of prior surgery (n=45) were 40 responders and 5 non-responders. Differences in marker levels between groups were determined using Mann-Whitney U-tests. Area under the curve (AUC) values were generated using receiver operating characteristics (ROC) statistics.

Results
In patients with history of prior surgery, PRO-C22 was higher at baseline in responders than non-responders (P=0.004). At week 14, responders had higher levels of PRO-C6 than non-responders (P&lt;0.05). Biomarkers PRO-C6 and PRO-C22 demonstrated predictive value at baseline (AUC [95% CI]: PRO-C6 0.78 [0.55–1.0], P=0.012; PRO-C22 0.90 [0.73–1.0], P&lt;0.001). At week 14, PRO-C6 was also able to discriminate between responders and non-responders (AUC [95% CI]: 0.82 [0.54–1.0], P&lt;0.01). No significant differences were observed in patients without history of prior surgery (Figure 1).

Conclusion
In patients with a history of prior surgery, higher baseline levels of PRO-C22 predict treatment response to IFX, whereas PRO-C6 levels were higher at week 14 after treatment initiation. These biomarkers demonstrated promising results in predicting response to anti-TNFα treatment, as well as separating responders from non-responders at week 14. Together, these markers could be used to predict and monitor treatment response to IFX in patients with CD with surgical history and may shed light on different profiles of ECM turnover. Future studies are warranted to further validate the potential utility of these biomarkers in larger patient cohorts.