Baseline predictors of response to TNF-α blocking therapy in ankylosing spondylitis

Identifying the characteristics of patients with ankylosing spondylitis (AS) before start of treatment which are able to predict a beneficial response to tumor necrosis factor-alpha (TNF-α) blocking therapy is relevant, especially in view of the high costs and potential side-effects of these agents. This review provides an overview of clinical trials and observational studies investigating baseline predictors of response after 3-6 months of TNF-α blocking therapy and baseline predictors of long-term anti-TNF-α treatment continuation in AS.

In multiple studies, increased acute phase reactants, higher disease activity, higher functional status, younger age, and HLA-B27 positivity were identified as independent baseline predictors of achieving clinical response to TNF-α blocking therapy. Increased acute phase reactants, presence of peripheral arthritis, and male sex were repeatedly identified as independent baseline predictors of anti-TNF-α treatment continuation.

Several studies using multivariate analyses identified comparable baseline predictors of response and/or continuation of TNF-α blocking therapy. The single predictors identified have, at best, moderate capacity to predict treatment response in the individual patient. The development of a prediction model may lead to a more robust instrument to support physicians in decision making on TNF-α blocking therapy in AS in daily clinical practice.