Postinduction serum infliximab trough level and decrease of C-reactive protein level are associated with durable sustained response to infliximab: a retrospective analysis of the ACCENT I trial.
Bottom Line: Optimal predictors of durable sustained response to maintenance infliximab 5 mg/kg were week 14 trough level ≥3.5 µg/mL and ≥60% CRP decrease (ORs (95% CI), 3.5 (1.1 to 11.4) and 7.3 (1.4 to 36.7)), respectively, in patients with raised baseline CRP (>8.0 mg/L); area under the ROC curve was 0.75 for both predictors.A ≥3.5 µg/mL week 14 infliximab serum level did not predict durable sustained response to 10 mg/kg maintenance infliximab.Serum infliximab trough levels ≥3.5 µg/mL and ≥60% CRP decrease were significantly associated with durable sustained response.
Affiliation: Department of Immunology, Janssen Biologics BV, Leiden, The Netherlands.Show MeSH
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Mentions: The median (IQR) CRP decrease was −2.0 (−13.0 to 0.0) mg/L in the maintenance infliximab 5 mg/kg group (n=144) and −13.0 (−30.0 to −6.0) mg/L in patients with raised baseline CRP (n=71). The median (IQR) CRP decrease was −3.0 (−17.0 to 0.0) mg/L in the maintenance infliximab 10 mg/kg group (n=140) and −12.0 (−25.0 to −5.0) mg/L in patients with raised baseline CRP (n=80). ROC curves were constructed to assign optimal cut-off values associated with sustained response to scheduled maintenance infliximab 5 mg/kg (figure 1). Areas under the ROC curves were 0.75 for CRP decrease (in patients with raised baseline CRP) and 0.75 for week 14 serum infliximab trough levels. Sensitivity, specificity, PPV and NPV were determined for predicting sustained response to scheduled maintenance infliximab 5 mg/kg with these two parameters (table 3). The 3.5 µg/mL week 14 serum infliximab trough level and 60% CRP decrease had NPVs of 0.83 and 0.93, respectively. Sensitivity and NPV further increased to 0.95 and 0.96, respectively, if the cut-off points, for example, a 3.5 µg/mL week 14 serum infliximab level or a 60% CRP decrease, were considered in combination (table 3).
Affiliation: Department of Immunology, Janssen Biologics BV, Leiden, The Netherlands.