Takayasu Arteritis Clinical Trial in China

Takayasu arteritis (TAK) is a rare form of large-vessel vasculitis, characterized by immune -induced vascular inflammation, resulting in the stenosis and occlusion of blood vessels \[1\]. TAK is observed predominantly in Asian females under 40 years of age \[2, 3\]. The stenosis or occlusion of blood vessels can cause severe ischemic events (e.g., acute myocardial infarction, stroke, death) involving multiple organs. Patients with TAK experience impaired quality of life \[4\] and face a significantly higher risk of death compared with that in the sex- and age-matched general population, with a standardized mortality ranging from 2.7 to 17.3 \[5, 6, 7\]. Thus, timely and efficacious treatment is important to improve the prognosis in such a young population. Glucocorticoids (GCs) are the first-line therapy for active TAK \[8, 9\]. High-dose GCs are initially efficacious. However, disease recurrence can occur in approximately 60% patients during the GCs tapering \[10, 11\]. Prolonged use of GCs is associated with significant toxicity, including glucose-metabolism disorders, cardiovascular adverse events (AEs), and osteoporosis \[12, 13\]. Therefore, immunosuppressive therapy is required to minimize the dose and duration of GC exposure \[8, 9\]. Conventional immunosuppressants have been recommended as GC-tapering agents for active TAK, whereas biological agents are recommended in refractory cases \[8, 9\]. Most previous studies focused on TAK treatment have been observational, only five randomized clinical trials (RCTs) are found, among which, just one study reported the effect of conventional immunosuppressants mycophenolate \[14, 15, 16, 17, 18\]. Thus, high-quality evidence to support therapeutic options of conventional immunosuppressants is very limited. Leflunomide (LEF) is a conventional immunosuppressant \[19\], which has shown satisfied GC-tapering effects in the treatment of giant cell arteritis, another large vessel vasculitis, in several observational studies \[20, 21, 22\]. In 2012, the first open-label study of 14 TAK patients demonstrated that 70% of patients could achieve at least partial clinical remission, and the GC dose could be reduced by 50% during LEF treatment \[23\]. Since then, several observational cohort or case-control studies have reported the efficacy of LEF for active TAK \[24, 25, 26, 27, 28, 29\]. A most recent study reported a comparable complete response rate of LEF (78%) versus adalimumab (88%) at 15-month follow-up \[30\]. Thus, LEF would be a promising alternative treatment for TAK, but evidence from RCTs is lacking. We conducted this multicenter, randomized, double-blind, placebo-controlled trial to investigate the efficacy and safety of LEF versus placebo combined with prednisone for active TAK, namely "Takayasu arteritis clinical trial in China" (TACTIC; ClinicalTrials.gov identifier: NCT02981979).