Tu1289 Preventing Crohn's Disease Recurrence After Resection With Adalimumab: Role of Drug and Anti-Drug Antibody Levels

remission at 3 months did not then undergo colectomy, yet 3/6 (50%) not in remission did (p=0.07). Bivariate comparisons for primary and secondary endpoints are tabulated below. Also, ROC analysis showed that the area under curve (AUC) of consecutive day 1 to 3 levels for serum IFX (cutoff ≤158 μg/ml), CRP (≤33 mg/L) and FC (≤4910 μg/ml) each predicted the primary endpoint (6w) with a sensitivity & specificity of 83% & 71% (AUC 0.81 [95% CI 0.57, 1.0]), 83% & 57% (AUC 0.75 [0.41, 1.0]) and 83% & 100% (AUC 0.88 [0.66, 1.0] respectively. Conclusions: Post-first IFX dose in ASUC early higher CRP and FC levels predicted poorer week 6 outcomes. Yet unexpectedly, an early decrement in IFX levels from day 1 through day 3 appeared to confer better outcomes; this might reflect appropriate IFX binding/utilization in early responders compared to static levels in potential non-responders (e.g. where a non-TNF pathway predominates). Further prospective evaluation of the predictive value of Day 1-3 biomarkers in ASUC is warranted given these findings.