CASE BASED REVIEW Successful treatment of adult-onset Still’ s disease with tocilizumab monotherapy: two case reports and literature review Ryota Sakai & Hayato Nagasawa & Eiko Nishi & Ayumi Okuyama & Hirofumi Takei & Takahiko Kurasawa & Tsuneo Kondo & Koji Nishimura & Yuichiro Shirai & Tatsuya Ito & Hideto Kameda & Tsutomu Takeuchi & Koichi Amano Received: 2 November 2011 / Accepted: 15 December 2011 / Published online: 4 January 2012 # Clinical Rheumatology 2011 Abstract Adult-onset Still’ s disease (AOSD) is a systemic inflammatory disease of unknown etiology. Recently, it has been reported that quite a few cases of refractory AOSD were successfully treated with tocilizumab (TCZ) and cor- ticosteroids were withdrawn in some of these patients. We report two AOSD patients who were treated successfully with TCZ monotherapy; thus, avoiding corticosteroid treat- ment. Because both of the patients refused to take cortico- steroids, we planned to treat them with 8 mg/kg of TCZ monotherapy at weeks 0, 2, 6 and subsequently every 4 weeks. The efficacy of TCZ was assessed by patients’ clinical symptoms such as fever, arthralgia, skin eruptions, and laboratory markers such as serum levels of CRP, ferritin, and IL-6. We also reviewed 14 previous case reports includ- ing 30 cases who had been treated with TCZ for AOSD. Our patients responded rapidly and have been maintained in clinical remission without corticosteroid treatment. In the literature review, concomitant corticosteroid treatment described in 13 cases was successfully tapered in 7 and discontinued in 6 cases. TCZ monotherapy can be a candi- date for the first-line therapy for some AOSD patients. Keywords Adult-onset Still’ s disease . Interleukin-6 . Monotherapy . Tocilizumab Introduction Adult-onset Still’ s disease (AOSD) is a systemic inflamma- tory disease of unknown etiology and is characterized by remittent fever, evanescent salmon pink rash, and polyar- thralgia frequently accompanied by neutrophilic leukocyto- sis [1, 2]. AOSD treatment comprises non-steroidal anti- inflammatory drugs (NSAIDs), corticosteroids, and immu- nosuppressive drugs such as methotrexate (MTX) [3]. Cor- ticosteroids, in particular, still provide mainstay AOSD therapy despite various adverse effects [3]. Recently, numerous studies have revealed that proinflam- matory cytokines such as IL-1, IL-6, IL-18, tumor necrosis factor (TNF), and interferon-gamma are involved in AOSD’ s pathogenesis [4, 5]. In fact, AOSD patients have been successfully treated with anti-cytokine therapies such as with TNF-α blocking agents [6, 7], an IL-1 receptor antagonist (anakinra) [8, 9], and an anti-IL-6 receptor mono- clonal antibody (tocilizumab, TCZ) [10–23]. Most of the cases are refractory to conventional therapies including high-dose corticosteroids and immunosuppressive drugs (cyclosporin and methotrexate, etc.) [11, 14, 16–18, 20, 22]. Among these case reports, TCZ seems to be highly R. Sakai (*) : H. Nagasawa : E. Nishi : A. Okuyama : H. Takei : T. Kurasawa : T. Kondo : K. Nishimura : Y. Shirai : T. Takeuchi : K. Amano Department of Rheumatology and Clinical Immunology, Saitama Medical Center, Saitama Medical University, 1981 Kamoda, Kawagoe 350-8550, Japan e-mail: r_sakai@saitama-med.ac.jp H. Kameda : T. Takeuchi Division of Rheumatology, Department of Internal Medicine, School of Medicine, Keio University, Tokyo, Japan T. Ito Department of Internal Medicine, Saitama Yorii Hospital, Yorii, Japan Clin Rheumatol (2012) 31:569–574 DOI 10.1007/s10067-011-1917-9