Ayaka Maeda, Yohei Kirino, Naomi Tsuchida, Yuri Uchiyama, Daisuke Kobayashi, Tomoyuki Asano, Yuji Ito, Kosuke Katsuo, Ayaka Kato, Ichiro Mori, Hiroyuki Yamaguchi, Toshimasa Shimizu, Satoshi Kobayashi, Mitsumasa Kishimoto, Nobuhiro Oda, Ryo Rokutanda, Ken Nagahata, Hiroshi Fujiwara, Hiroshi Kobayashi, Yoichi Takeuchi, Hiroyuki Hagiyama, Naoki Umeda, Kaori Uchino, Yuji Miyoshi, Yukiko Hidaka, Hiroaki Ida, Keiichi Akasaka, Kaori KASHINO, Yusuke Yoshida, Hidenori Ohnishi, Noriyuki Takahashi, Yuichiro Fujieda, Nobuyuki Horita, Kaoru Takase‐Minegishi, Naomichi Matsumoto, Hideaki Nakajima
OBJECTIVES: VEXAS (vacuoles, E1 enzyme, X-linked, autoinflammatory, somatic) syndrome is an autoinflammatory disease caused by somatic variants of the UBA1 gene. Due to uncertainty around treatment strategies and limited therapeutic options, this study aimed to characterise the clinical treatment and outcomes of VEXAS syndrome patients in Japan. METHODS: We retrospectively analysed data on clinical manifestations, treatments, and outcomes from 46 male patients diagnosed with VEXAS syndrome. Twelve patients at our institution were evaluated for remission using the French VEXAS group criteria. RESULTS: All patients (median age at onset: 71.4 years) received systemic glucocorticoid therapy (mean maximum dose: 47.4 mg/day; mean minimum dose: 8.5 mg/day). Most patients required continuous glucocorticoid treatment of ≥10 mg/day, and tapering was generally difficult. Among the patients followed at our institution, only 42% (5/12) achieved complete remission at least once during follow-up. Tocilizumab was the most frequently administered immunosuppressant (n = 24, 52.2%); Janus kinase inhibitors and azacitidine, reported to be effective overseas, were prescribed in only three and two cases, respectively. CONCLUSIONS: This study highlights the difficulty of treating patients with VEXAS syndrome in Japan. The development of more effective treatments is urgently needed to reduce glucocorticoid dependence and improve patient outcomes.