Serological Markers as Predictors of Anti-TNF Response in Children with Crohn's Disease.

Background: To advance personalized medicine in pediatric Crohn's disease (CD), we aimed to explore the utility of serological biomarkers in predicting response to anti-tumor necrosis factor (TNF).

Methods: Children with CD were enrolled at initiation of anti-TNF and followed prospectively at 4 and 12 months thereafter, as well as at last follow-up. At baseline, 10 serological markers of the "PROMETHEUS® IBD sgi Diagnostic test" were measured, including pANCA, ASCA IgG and IgA, anti-CBir1, anti-OmpC, anti-A4-Fla2, anti-Fla-X, SAA, ICAM-1 and VCAM-1. The primary outcome was sustained steroid-free remission (SSFR, i.e. clinical remission without steroids at both 4 and 12 months) and the secondary outcome was primary non-response (PNR).

Results: Of the 72 included children (mean age, 12.8 ± 3.1 years; median disease duration, 6.4 months [IQR 2.5-17.3]), 42 (58%) were treated with adalimumab and 30 (42%) with infliximab. PNR was noted in 20 (28%) children and failure to achieve SSFR in 36 (50%). The most common positive serological markers were SAA (86%) and ICAM-1 (82%). In univariate analyses, none of the serological markers achieved statistical significance in association with SSFR or with PNR. In multivariable analysis, positivity of ASCA IgG (OR 3.3 [95%CI 0.8-14.4]) and pANCA (OR 5.3 [95%CI 0.9-48]) were the closest to achieving significance in predicting SSFR, with fair predictive performance for the model (AUC 0.67 [95%CI 0.55-0.80]).

Conclusion: The serological markers tested here have limited utility in predicting response to anti-TNF treatment. Further studies with larger sample sizes are needed to confirm the utility of ASCA IgG and pANCA.