Azathioprine vs methotrexate in eosinophilic granulomatosis with polyangiitis: a monocentric retrospective study

Objectives: To analyse the effectiveness, safety and steroid-sparing effect of AZA and MTX as induction of remission and maintenance treatment in eosinophilic granulomatosis with polyangiitis. Methods: We retrospectively collected data from 57 patients divided into four groups according to treatment: MTX/AZA as first-line agents (MTX1/AZA1) in non-severe disease or as second-line maintenance therapy (MTX2/AZA2) in severe disease previously treated with CYC/rituximab. During the first 5 years of treatment with AZA/MTX we compared the groups according to: remission rate [defined as R1: BVAS ¼ 0; R2: BVAS ¼ 0 with prednisone ≤5 mg/day; R3 (MIRRA definition): BVAS ¼ 0 with prednisone ≤3.75 mg/day], persistence on therapy, cumulative glucocorticoid (GC) dose, relapse and adverse events (AEs). Results: There were no significant differences in remission rates (R1) in each group (63% in MTX1 vs 75% in AZA1, P ¼ 0.53; 91% in MTX2 vs 71% in AZA2, P ¼ 0.23). MTX1 allowed R2 more frequently in the first 6 months compared with AZA1 (54% vs 12%, P ¼ 0.04); no patients receiving AZA1 achieved R3 up to the first 18 months (vs 35% in MTX1, P ¼ 0.07). The cumulative GC dose was lower for MTX2 vs AZA2 (6 g vs 10.7 g at 5 years, P ¼ 0.03). MTX caused more AEs compared with AZA (66% vs 30%, P ¼ 0.004), without affecting the suspension rate. No differences emerged in time-to-first relapse, although fewer patients treated with AZA2 had asthma/ENT relapses (23% vs 64%, P ¼ 0.04). Conclusion: A significant proportion of patients achieved remission with both MTX and AZA. MTX1 had an earlier remission on a lower GC dose but MTX2 had a better steroid-sparing effect.