Adalimumab drug and antibody levels as predictors of clinical and laboratory response in @entity1 with XXXX .

@entity1 @entity30 @entity1851
BACKGROUND: Adalimumab is an effective treatment for @entity30 ( @entity30 ). Anti-adalimumab antibodies (AAA) and low trough serum drug concentrations have been implicated as pre-disposing factors for treatment failure. AIMS: To assess adalimumab and AAA serum levels, and to examine their association and discriminatory ability with clinical response and serum @entity1851 ( @entity1851 ). METHODS: We performed a cross-sectional study using trough sera from adalimumab-treated @entity30 @entity1 . Demographical data, Montreal classification, treatment regimen and clinical status were recorded. Serum adalimumab, AAA and @entity1851 were measured. 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. RESULTS: One hundred and eighteen trough serum samples were included from 71 @entity1 . High adalimumab trough serum concentration was associated with disease remission (Area Under Curve 0.748, P < 0.001). A cut-off drug level of 5.85  g/mL yielded optimal sensitivity, specificity and positive likelihood ratio for remission prediction (68%, 70.6% and 2.3, respectively). AAA were inversely related with adalimumab drug levels (Spearman's r = -0.411, P < 0.001) and when subdivided into categorical values, positively related with disease activity (P < 0.001). High drug levels and stricturing vs. penetrating or inflammatory phenotype, but not AAA levels, independently predicted disease remission in a multivariate logistic regression model. CONCLUSIONS: 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.
