Anti-drug antibodies and low serum trough infliximab levels correlate with disease activity measures in spondyloarthritis patients on an as-needed infliximab treatment.

Spondyloarthritis patients on low-dose, as-needed infliximab therapy, have both the trough infliximab and anti-drug antibodies correlate significantly with the measures of disease activity. We hypothesize that trough infliximab levels and anti-drug antibodies may be used to predict a suboptimal response due to secondary resistance in SpA patients.