Adding Azathioprine to Glucocorticoid Regimen Doesn’t Improve SNV Remission Rates, Study Finds

The addition of azathioprine, an immunosuppressant, to a glucocorticoid treatment regimen does not improve remission rates for patients with non-severe systemic necrotizing vasculitides (SNVs), a new study shows.

The study, “Adding Azathioprine to Remission-Induction Glucocorticoids for Eosinophilic Granulomatosis With Polyangiitis (Churg-Strauss), Microscopic Polyangiitis, or Polyarteritis Nodosa Without Poor Prognosis Factors,” appeared in the journal Arthritis & Rheumatology.

Eosinophilic granulomatosis with polyangiitis (EGPA), microscopic polyangiitis (MPA) and non-hepatitis B virus-associated polyarteritis nodosa (PAN) are SNVs whose treatment remains a subject of debate.

Patients with severe SNVs receive both glucocorticoids and immunosuppressants. Most patients with non-severe SNVs, however, are treated with glucocorticoids alone. Yet one-third of these patients experience a relapse within two years, so their optimal treatment remains controversial.

To address this, a group of researchers conducted a clinical trial (NCT00647166) to determine whether adding azathioprine to glucocorticoids to treat non-severe SNVs could improve the sustained remission rate.

All patients recruited for this study received glucocorticoids and then randomly received either placebo or azathioprine for 12 months. Participants were grouped according to their SNV, which was either EGPA or MPA/PAN. The primary endpoint was the rate of patients who failed to achieve remission or had minor or major relapses at 24 months.

At 24 months, 47.8 percent of those on azathioprine failed to achieve remission or had a relapse, compared to 49 percent of those receiving placebo, indicating essentially no change in remission rates.

The rates were also similar when looking at the initial remission rates, which were 95.7 percent vs. 87.8 percent, as well as the total relapse rates which were 44.2 percent for those on azathioprine versus 40.5 percent for those on placebo.

In terms of adverse events, 47.8 percent of patients in the azathioprine arm experienced one or more severe adverse events, compared to 46.2 percent in the placebo arm, indicating little or no difference between the groups.

In particular, patients with EGPA in both groups had comparative rates in asthma or rhinosinusitis exacerbations.

The absence of azathioprine efficacy in sustaining remission could not be attributed to either a low dose or a short duration, as the dose given is usually administered in clinical practice and most patients were still taking azathioprine at 12 months.

Therefore, the authors concluded that “addition of azathioprine 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.”