Maintenance therapy is associated with better long-term outcomes in adult patients with primary angiitis of the central nervous system.

Objective: We aimed to analyse the effect of maintenance therapy after induction on the outcomes of adult patients with primary angiitis of the CNS (PACNS).

Methods: We analysed long-term outcomes (relapse, survival and functional status) of patients enrolled in the French multicentre PACNS cohort who achieved remission after induction treatment and with ⩾12 months' follow-up, according to whether or not they received maintenance therapy. Good outcome was defined as relapse-free survival and good functional status (modified Rankin scale ⩽ 2) at last follow-up.

Results: Ninety-seven patients [46 (47%) female, median age: 46 (18-78) years at diagnosis] were followed up for a median of 55 (5-198) months. Induction treatment consisted of glucocorticoids in 95 (98%) patients, combined with an immunosuppressant in 80 (83%) patients, mostly CYC. Maintenance therapy was prescribed in 48 (49%) patients, following CYC in 42 of them. Maintenance therapy was started 4 (3-18) months after glucocorticoid initiation. At last follow-up, good outcomes were observed in 32 (67%) patients who had received maintenance therapy vs 10 (20%) who had not (P < 0.0001). Thirty-two (33%) patients experienced relapse [10 (22%) had received maintenance therapy while 22 (45%) had not, P = 0.01]; four subsequently died from relapse. In the multivariate analysis, maintenance therapy was the only independent predictor of good outcome [odds ratio (OR) = 7.8 (95% CI: 3.21, 20.36), P < 0.0001].

Conclusion: The results of this long-term follow-up study suggest that maintenance therapy in adults with PACNS is associated with better functional outcomes and lower relapse rates. Further studies are needed to confirm these findings.