Background Adult-onset Still’s disease (AOSD) is an inflammatory condition of unknown origin.We previously reported that non-steroidal anti-inflammatory drugs, steroids and immunosuppressive drugs such as methotrexate (MTX) and cyclosporin (CsA) successfully control the disease in 60% of patients (pts).(1)Growing evidences support the use of biologic agents such as anakinra,tocilizumab-(TCZ) and TNF-alpha blocking agents in refractory forms of AOSD.(2,3)

Objectives To assess the long-term efficacy and safety of biologic agents in pts with AOSD in terms of systemic features, disease markers and dose reduction of the immunosuppressive and steroid drugs.

Methods Sixteen Italian pts with refractory AOSD were treated with anakinra,TCZ,etanercept or adalimumab.Complete response (CR) was defined as the absence of joint swelling,systemic symptoms,normal acute phase reactants and steroid dose reduction by 50% or more for at least 2 months.Clear improvement without normalization of acute phase reactants and steroid dose reduction by less then 50% were considered partial response (PR).Treatment failure was defined as persistent or worsening of systemic manifestation and acute phase reactants despite ongoing treatment for at least 2 months.

Results Sixteen pts with AOSD treated with biologic agents were followed-up at our institution from 1998 to 2012.The mean age (range) at the diagnosis was 33.1 years (16-55), disease duration was 6.6 years (2–12) and the mean follow-up time after the beginning of biologic agents was 42.5 months (8–80).All pts were treated with anakinra; 10 pts (63%) achieved CR, 2 pts (12%) achieved PR and 4 pts (25%) did not respond.Among non responders, 2 pts were treated with etanercept without benefit: thus, one received TCZ with PR, and one adalimumab with CR.The remaining 2 non responder pts are now starting TCZ.Steroid treatment was discontinued in 9 pts (56%) that achieved CR; in the remaining 7 pts (44%), the steroid dose was decreased by 25 to 94%. Three pts (19%) resumed immunosuppressive agents, 5 pts (30%) maintained MTX at the initial dose, 6 pts (38%) reduced MTX by 50% to 63% and 2 pts (13%) reduced CsA by 37 to 50%.Mild reactions to injections were the most frequent adverse events although herpes zoster infection developed in 2 pts treated with anakinra and in 1 treated with TCZ.

Conclusions The present study describes the longest follow-up assessing the long-term efficacy and tolerability of biologic agents in refractory AOSD.In particular, anakinra was effective in the majority of AOSD affected pts, except in 2 pts in which adalimumab and TCZ provided CR and PR respectively.Treatment with biologic agents, either ensuring a CR or a PR, prompted a significant reduction in the overall dose of steroid and immunosuppressive drugs.

1. Franchini S,et al. Efficacy of traditional and biologic agents in different clinical phenotypes of adult-onset Still’s disease. Arthritis Rheum 2010;62:2530-5.

2. Lequerré T,et al. Interleukin-1 receptor antagonist (anakinra) treatment in patients with systemic-onset juvenile idiopathic arthritis or adult onset Still disease: preliminary experience in France. Ann Rheum Dis 2008;67:302-8.

3. Sakai R,et al. Successful treatment of adult-onset Still’s disease with tocilizumab monotherapy: two case reports and literature review. Clin Rheumatol 2012

Disclosure of Interest None Declared