Biological treatments for SAPHO syndrome: an update.

Synovitis, Acne, Pustulosis, Hyperostosis and Osteitis (SAPHO) syndrome is a rare and often unrecognized disease with prominent inflammatory cutaneous and articular manifestations. Since the identification of the syndrome many immunosuppressive drugs have been used for the management of SAPHO, with variable results. The use of anti- TNF-α agents as a therapeutic option for SAPHO cases unresponsive or refractory to conventional drugs, demonstrated their efficacy for bone, skin and joints manifestations. TNF-α is a pro-inflammatory cytokine and pivotal regulator of other cytokines, including IL-1 β , IL-6 and IL-8, involved in inflammation, acute-phase response induction and chemotaxis. IL-1 inhibition strategies with Anakinra have proven their efficacy as first and second line treatment. We herein review the literature concerning the use of biological drugs in patients with SAPHO syndrome. In addition, we describe for the first time the use of Ustekinumab, an antibody against the p40 subunit of IL-12 and IL-23, after failure of multiple drugs including anti-TNF-α and Anakinra. This anti-IL12/IL23 agent could be a promising therapeutic option, also considering the opportunity to interfere with the IL23/TH17 pathway, which we recently found disturbed. Furthermore, a rationale emerges for the use of the new anti-IL-1 antagonists or the IL-17 blockade, in particular for the most difficult-to-treat SAPHO cases.