Adalimumab is an effective treatment for Crohn's disease (CD).
Anti-adalimumab antibodies (AAA) and low trough serum drug concentrations have been implicated as pre-disposing factors for treatment failure.
Dr Mazor and colleagues from Israel assessed adalimumab and anti-adalimumab antibodies serum levels, and examined their association and discriminatory ability with clinical response and serum C-reactive protein (CRP).
The researchers performed a cross-sectional study using trough sera from adalimumab-treated CD patients.
Demographical data, Montreal classification, treatment regimen and clinical status were recorded.
Serum adalimumab, anti-adalimumab antibodies and CRP were measured.
|A cut-off drug level of 5.85 μg/mL yielded optimal sensitivity|
|Alimentary Pharmacology & Therapeutics|
Receiver operating characteristic analysis and a multivariate regression model were performed to find drug and antibody thresholds for predicting disease activity at time of serum sampling.
The research team found that 118 trough serum samples were included from 71 patients.
High adalimumab trough serum concentration was associated with disease remission.
The team noted that a cut-off drug level of 5.85 μg/mL yielded optimal sensitivity, specificity and positive likelihood ratio for remission prediction.
The researchers found that anti-adalimumab antibodies were inversely related with adalimumab drug levels, and when subdivided into categorical values, positively related with disease activity.
High drug levels and stricturing vs. penetrating or inflammatory phenotype, but not anti-adalimumab antibodies levels, independently predicted disease remission in a multivariate logistic regression model.
Dr Mazor's team concludes, "Adalimumab drug levels were inversely related to disease activity."
"High levels of anti-adalimumab antibodies were positively associated with disease activity, but this association was mediated mostly by adalimumab drug levels."