Optimizing anti-TNF therapy in Behçet's disease: the role of therapeutic drug monitoring.

Behçet's disease (BD) is a complex, relapsing multisystem disorder characterized by autoinflammatory features. Because disease-specific diagnostic biomarkers are lacking and clinical presentation varies according to geographic background and organ involvement, diagnosis may be delayed, particularly in non-endemic regions and in patients with atypical manifestations. Therapeutic management is highly individualized and guided by disease severity and dominant organ involvement. Severe, refractory, or organ-threatening disease often requires aggressive immunosuppressive treatment, including targeted biologic therapy with monoclonal anti-tumor necrosis factor (anti TNF) alpha agents such as infliximab and adalimumab. Therapeutic drug monitoring (TDM), based on serum trough drug concentrations and anti-drug antibodies, is routinely used to optimize anti-TNF therapy in inflammatory bowel disease and is increasingly discussed in other immune-mediated inflammatory diseases treated with monoclonal antibodies. In Behçet's disease, however, TDM is not yet standard practice, and Behçet-specific therapeutic trough targets for infliximab and adalimumab have not been validated. Nevertheless, integrating TDM with clinical assessment may support more individualized decision-making by helping distinguish insufficient drug exposure, immunogenicity, and pharmacodynamic failure. In this article, we discuss the rationale for TDM in anti-TNF-treated BD, summarize the current direct and indirect evidence, and propose a cautious, clinically guided approach. Behçet's disease; infliximab; adalimumab; anti-TNF therapy; therapeutic drug monitoring; trough levels; anti-drug antibodies; treatment optimization.