Higher postinduction infliximab concentrations tied to improved outcomes in fistulizing CD

Higher concentrations of infliximab postinduction appear to result in early and long-term favourable therapeutic outcomes in patients with fistulizing Crohn’s disease (CD), a study has found.

The investigators carried out a posthoc analysis of the ACCENT-II trial, evaluating patients with fistulizing CD on induction (n=282) and maintenance infliximab therapy (n=139).

The following therapeutic outcomes were examined at weeks 14 and 54: fistula response, complete fistula response, C-reactive protein (CRP) normalization (≤5 mg/L) in patients with an elevated baseline CRP, and a more stringent outcome of composite remission, defined as combined complete fistula response and CRP normalization.

Multivariable logistic regression models were generated to evaluate the associations between serum infliximab concentrations and outcomes.

Higher infliximab concentrations at week 14 independently correlated with week-14 fistula response (odds ratio [OR], 1.16, 95 percent confidence interval [CI], 1.02–1.32; p=0.019) and composite remission (OR, 2.32, 95 percent CI, 1.55–3.49; p<0.001). Higher week-14 infliximab concentrations also correlated with week-54 composite remission (OR, 2.05, 95 percent CI, 1.10–3.82; p=0.023).

In receiver operating characteristic curve analysis, week-14 composite remission was associated with week-14 infliximab concentrations thresholds with combined maximal sensitivity and specificity of ≥20.2 μg/mL at week 2, ≥15 μg/mL at week 6, and ≥7.2 μg/mL at week 14.

“The results of this study might help better guide infliximab therapy in patients with fistulizing CD,” the investigators said.

Of note, whether accelerated dosing in some patients with subtherapeutic drug exposure might lead to improved outcomes requires further research.