Decreased clinical response to adalimumab in ankylosing spondylitis is associated with antibody formation

Treatment with anti-tumour necrosis factor (TNF) is very effective in most patients with ankylosing spondylitis (AS), but inefficacy occurs in about 40% of cases.1 Antibody formation against TNF blocking agents is an increasingly recognised problem;2 however, no data have yet been reported on antibody formation against adalimumab (anti-adalimumab) in AS. Lack of response can be explained in two ways: (1) TNF might not be important for disease activity in certain patients; and (2) TNF inhibition might be insufficient. The latter could be caused by excessive production of TNF, low compliance of the patient, insufficient dosing or an enhanced clearance of adalimumab due to antibody formation. Adalimumab is a fully human monoclonal antibody against TNF but, despite this fact, an immune response …