Corticosteroid-free treatment of tocilizumab monotherapy for microscopic polyangiitis: a single-arm, single-center, clinical trial

<i>Objectives</i>: To assess the efficacy of tocilizumab (TCZ) monotherapy for the remission induction of microscopic polyangiitis (MPA) in a prospective single-arm, single-center, cohort, pilot study. <i>Methods</i>: Eligible patients were aged between 20 and 80 years and were newly diagnosed with MPA according to Watts’ classification algorithm. Seven patients received 8 mg/kg of intravenous TCZ fortnightly for the first 2 months (5 courses), and monthly for the next 10 months (10 courses). One year after TCZ monotherapy, the patients were followed-up without any treatment. The protocol did not permit the use corticosteroids or any other immunosuppressants. Complete remission (CR) was defined as the Birmingham Vasculitis Activity Score of 0 at two consecutive visits made at least a month apart. <i>Results</i>: CR was achieved in two of six patients (33.3%) at 6 months and three patients (50.0%) at 12 months. Two patients were withdrawn: one because of inefficacy at 6 weeks and the other because of flare at 6 months. One patient voluntarily withdrew after CR at 3 months. Four patients (66.7%) could be kept drug-free after 1 year of TCZ without relapse for 6–15 months at the last visit. <i>Conclusion</i>: TCZ monotherapy may be an alternative treatment strategy in some patients with MPA.

研究目标：在一项前瞻性单臂、单中心队列先导试验中，评估托珠单抗（tocilizumab, TCZ）单药治疗诱导显微镜下多血管炎（microscopic polyangiitis, MPA）缓解的疗效。研究方法：入组患者年龄介于20至80岁之间，且依据沃茨分类算法（Watts’ classification algorithm）新确诊为MPA。共7例患者接受静脉输注托珠单抗治疗：前2个月每两周给药1次，剂量为8 mg/kg，共计5个疗程；后续10个月每月给药1次，共计10个疗程。托珠单抗单药治疗满1年后，患者停止所有治疗并接受随访。本试验方案严禁使用糖皮质激素或其他任何免疫抑制剂。完全缓解（complete remission, CR）定义为两次间隔至少1个月的连续随访中，伯明翰血管炎活动度评分（Birmingham Vasculitis Activity Score）均为0。研究结果：6例患者中，有2例（33.3%）在治疗6个月时达到完全缓解，12个月时达到完全缓解的患者为3例（50.0%）。共有2例患者退出试验：1例因治疗6周时疗效不佳，另1例因治疗6个月时病情复发。另有1例患者在治疗3个月达到完全缓解后自愿退出试验。末次随访时，4例患者（66.7%）在接受1年托珠单抗单药治疗后实现无药维持，且6至15个月未出现疾病复发。研究结论：托珠单抗单药治疗可作为部分显微镜下多血管炎患者的替代治疗方案。