Effectiveness and safety of leflunomide compared with cyclophosphamide as induction therapy in Takayasu's arteritis: an observational study.

Aims: The objective of this study was to investigate the outcomes of leflunomide (LEF) compared with those of cyclophosphamide (CYC) as induction against active Takayasu's arteritis (TA) in Chinese patients.

Methods: This was an observational study based on a prospective cohort that included TA patients diagnosed in large third-level first-class general hospitals in East China from January 2009 to September 2018. LEF- or CYC-induced active patients were enrolled for comparative effectiveness analysis. One-to-more paired cohorts of LEF CYC were derived by propensity-score matching (PSM). The primary outcome was complete remission (CR) at 9-month follow up, and secondary endpoints included partial remission (PR) and effectiveness rate (ER). Multivariable logistic regression was used to identify statistical significance.

Results: A total of 131 enrolled patients with at least 3-months treatment included 53 receiving a regimen of glucocorticoid (GC) and LEF and 78 receiving GC and CYC. Compared with the CYC group, the LEF group showed higher CR rate {LEF CYC: 84.6% [95% confidence interval (CI) 74.5-94.8%] 59.0% (47.8-70.1%); relative risk (RR) = 0.3 (0.1-0.6),  = 0.002} and lower daily GC dose [10.0 (5.0-12.5) 12.5 (10.0-15.0) mg,  = 0.043] at the end of the 9-month induction. In the matched analysis, the LEF group ( = 23) still indicated a higher CR rate than the CYC group ( = 54) after PSM [RR = 0.1 (0.0-0.6),  = 0.003]. Four LEF-treated patients had mild side effects, and one died unrelated to LEF.

Conclusion: LEF could be an alternative induction therapy against TA, showing good effectiveness and tolerance compared with CYC.