Does leflunomide have a role in giant cell arteritis? An open-label study

Glucocorticoid monotherapy has been the mainstay treatment of giant cell arteritis (GCA) for decades. We aimed to evaluate the role of leflunomide as a steroid-sparing agent in GCA. This open-label study included incipient GCA patients followed for at least 48 weeks at a single secondary/tertiary rheumatology centre. At the time of diagnosis, patients received glucocorticoids. At week 12 of follow-up, leflunomide 10 mg qd was recommended as an adjunctive therapy to all patients without contraindications. The decision to start the leflunomide was patient-dependent. The number of relapses, a cumulative glucocorticoid dose during follow-up and treatment-related adverse events (AE) were recorded and compared between glucocorticoid-only and leflunomide groups. Seventy-six patients (65.8% female, median (IQR) age 73.7 (66.1-78.8) years) were followed for a median (IQR) 96 (86-96) weeks. Thirty out of 76 (39.5%) patients received leflunomide at week 12 (leflunomide group); the others continued treatment with glucocorticoid (glucocorticoid-only group). During the first 48 weeks of follow-up, 22 patients relapsed, 4 (13.3%) in leflunomide group and 18 (39.1%) in glucocorticoid-only group. The difference was statistically significant (p = 0.02; NNT 3.9 (95% CI 2.2-17.4)). Furthermore, 17/30 (56.7%) patients in the leflunomide group managed to stop glucocorticoid at week 48 (with one relapse (5.9%) shortly afterwards). The cumulative glucocorticoid dose at the last visit was lower in the leflunomide group than in the glucocorticoid-only group (p = 0.01). Our findings indicate the steroid-sparing effect of leflunomide in GCA.