Lack of anti-drug antibodies in patients with psoriasis well-controlled on long-term treatment with tumour necrosis factor inhibitors.

Psoriasis treatment has undergone a revolution with the use of tumour necrosis factor-alpha (TNF-α) inhibitors. Three TNF-inhibitors are registered for treatment of psoriasis. Unfortunately, not all patients respond favourably to anti-TNF treatment. Some patients either do not respond at all or have insufficient response, while others respond initially, but have later relapses despite increased dosage and/or more frequent administration of the drugs. The mechanisms underlying these response failures are not entirely understood (1). Immunogenicity is indeed a potential hazard of all protein drugs, and there is evidence that repeated injections of biopharmaceuticals trigger anti-drug antibody (aDAb) responses in some patients. Few studies have examined aDAb in patients with psoriasis (2–5). The aim of this study was to investigate the presence of aDAb/functional inhibitor levels in patients with psoriasis who have been well-controlled for > 18 months on 1 of the 3 TNF-inhibitors, along with functional blood levels of the drugs.