TNF-α antagonists beyond approved indications: stories of success and prospects for the future.

Tumour necrosis factor alpha (TNF-α) is a key molecule of the inflammatory response and data derived from studies in experimental animal models and humans suggest that TNF-α may be implicated in the pathogenesis of various autoimmune and non-infectious inflammatory conditions. Over the past decade pharmaceutical agents directed against TNF-α (infliximab, adalimumab and etanercept) have been widely and successfully employed for the management of rheumatoid arthritis (RA), ankylosing spondylitis (AS), psoriasis, psoriatic arthritis, juvenile idiopathic arthritis and inflammatory bowel disease, whereas two novel anti-TNF-α agents, golimumab and certolimumab pegol, recently entered the market for the treatment of RA, AS, Crohn's disease and psoriasis. Encouraged by the positive results obtained from the use of TNF-α antagonists in terms of efficacy and safety and due to the increasingly accumulating evidence regarding the implication of TNF-α in the pathogenesis of numerous disorders, anti-TNF-α agents have been considered for the management of diseases other than the ones they were initially approved for. Although in the case of multiple sclerosis and chronic heart failure the outcome from the administration of TNF-α blockers had been less than favourable, in other cases of non-infectious inflammatory conditions the response to TNF-α inhibition had been fairly beneficial. More specifically, according to well-documented clinical trials, anti-TNF-α agents exhibited favourable results in Behçet's disease, non-infectious ocular inflammation, pyoderma gangrenosum and hidradenitis suppurativa. In this review we discuss the successful outcomes as well as the prospects for the future from the off-label use of TNF-α antagonists.