Adding Azathioprine to Remission-Induction Glucocorticoids for Eosinophilic Granulomatosis With Polyangiitis (Churg-Strauss), Microscopic Polyangiitis, or Polyarteritis Nodosa Without Poor Prognosis Factors: A Randomized, Controlled Trial.

OBJECTIVE: In most patients with nonsevere systemic necrotizing vasculitides (SNVs), remission is achieved with glucocorticoids alone, but one-third experience a relapse within 2 years. This study was undertaken to determine whether the addition of azathioprine (AZA) to glucocorticoids could achieve a higher sustained remission rate of newly diagnosed nonsevere eosinophilic granulomatosis with polyangiitis (Churg-Strauss) (EGPA), microscopic polyangiitis (MPA), or polyarteritis nodosa (PAN).

METHODS: All patients included in this double-blind trial received glucocorticoids, gradually tapered over 12 months, and were randomized to receive AZA or placebo for 12 months, with stratification according to SNV (EGPA or MPA/PAN). The primary end point was the combined rate of remission induction failures and minor or major relapses at month 24.

RESULTS: Ninety-five patients (51 with EGPA, 25 with MPA, and 19 with PAN) met the inclusion criteria, were randomized, and received at least 1 dose of AZA (n = 46) or placebo (n = 49). At month 24, 47.8% of the patients receiving AZA versus 49% of the patients receiving placebo had remission induction failures or relapses (P = 0.86). Secondary end points were comparable between the AZA and placebo arms. These included initial remission rate (95.7% versus 87.8%), total relapse rate (44.2% versus 40.5%), and glucocorticoid use. Two patients in the placebo arm died; 22 patients in the AZA arm (47.8%) and 23 patients in the placebo arm (46.9%) experienced ≥1 severe adverse event. For EGPA patients, the primary end point (48% in the AZA arm versus 46.2% in the placebo arm) and the percent of patients who experienced asthma/rhinosinusitis exacerbations (24% in the AZA arm versus 19.2% in the placebo arm) were comparable between treatment arms.

CONCLUSION: Addition of AZA to glucocorticoids for the induction of remission of nonsevere SNVs does not improve remission rates, lower relapse risk, spare steroids, or diminish the EGPA asthma/rhinosinusitis exacerbation rate.