medwireNews: A post-hoc analysis of combined trial data suggests that extending azathioprine maintenance therapy beyond 18 months is not necessary for preventing relapses among patients with antineutrophil cytoplasmic autoantibody (ANCA)-associated vasculitis.
In an analysis of 380 patients with newly diagnosed disease who participated in six European multicenter studies and were followed up for a mean of 65.4 months after diagnosis, Anoek de Joode (University Medical Center Groningen, the Netherlands) and colleagues found that 84 participants experienced a first relapse during azathioprine maintenance therapy, while 71 relapsed after discontinuation.
When participants were grouped according to the duration of maintenance therapy after remission induction, which varied from less than 12 to 42 months, 65.3% of 301 patients receiving azathioprine for longer than 18 months after diagnosis were relapse-free at 60 months, compared with 55.0% of 51 who discontinued the drug at or before 18 months, a nonsignificant difference.
And when comparing azathioprine treatment duration of longer than versus up to 24, 36, and 48 months, there was a “numerically small and not statistically significant increase” in relapse-free survival rates.
“[O]n the basis of our findings, we think there is no clear evidence that extension of maintenance therapy with [azathioprine] beyond 18 months after diagnosis in general is effective in relapse prevention,” write the researchers in Rheumatology.
The team did, however, find that relapse-free survival was significantly associated with mode of induction therapy, with higher rates of relapse seen among patients treated with intravenous cyclophosphamide versus oral treatment (hazard ratio [HR]=1.21), and with ANCA specificity, in that participants with PR3-ANCA antibodies were more likely to experience relapses than those without (HR=1.32).
de Joode and colleagues note that their study was limited by its retrospective nature, and that participants’ clinical data were only collected at baseline. Furthermore, the findings “may not be applicable to certain groups of patients who may have higher risk of relapse or other specific characteristics,” they caution.
And the team concludes that the results of an ongoing “large multicentre maintenance of remission study comparing short- and long-term courses of [azathioprine] maintenance therapy,” should “enable clinicians in daily practice to decide what maintenance agent to choose and for how long.”
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