Patil A, et al. - Thirty-five adult spondyloarthritis (SpA) patients in the age group 18-70 years were included by the researchers in order to determine if the trough drug levels and anti-drug antibodies in patients with SpA treated with as-needed infliximab dosing had a correlation with the disease activity measures. A significant negative correlation between the trough infliximab levels and the Ankylosing Spondylitis Disease Activity Score – erythrocyte sedimentation rate (ASDAS-ESR) and Ankylosing Spondylitis Disease Activity Score – C-reactive protein (ASDAS-CRP) scores were observed. Sixty-seven percent of the patients had positive anti-drug antibodies as that of the antibody negative patients who had significantly higher ASDAS-ESR and ASDAS-CRP scores. Hence, patients with spondyloarthritis on low-dose, as-needed infliximab therapy had both the trough infliximab and anti-drug antibodies which were significantly related to the measures of disease activity. Therefore, to guess a suboptimal response due to secondary resistance in SpA patients, trough infliximab levels and anti-drug antibodies could be hypothetically used.