AAV treatment should be prolonged after remission achievement to obtain sustained remission and prevent relapses.
Several remission-sustaining candidates have been evaluated, including AZA, MTX, or mycophenolate mofetil (MMF). In a randomized controlled trial comparing AZA versus MTX for patients whose remissions had been obtained with glucocorticoids and pulse CYC, we demonstrated that, after a mean follow-up of 29 months, respective relapse rates were 36 versus 33%. AZA versus MMF to prevent relapses was also evaluated. This prospective randomized controlled trial showed that AZA was superior to MMF, leading to the conclusion that the latter should not be considered as the first-choice agent to maintain AAV remission.
RTX has clearly revolutionized AAV maintenance therapy. The results of the MAINRITSAN trial demonstrated RTX superiority over AZA, with, respectively, 5 versus 28% relapse rates at month 28. In that prospective randomized controlled trial, RTX maintenance consisted of 500-mg infusions every 6 months for 18 months. Those findings were confirmed by the clear between group difference after 60-month follow-up.
However, it also became clear that relapses still occurred, frequently 18 to 24 months after the last RTX infusion. Our long-term analysis of the MAINRITSAN trial data showed that, in addition to the presence or absence of PR3-ANCA at diagnosis, patients who remained PR3-ANCA–positive 12 months after starting maintenance therapy had more frequent relapses than those whose ANCA had disappeared at 12 months. ANCA reappearance is also a factor predictive of relapses or disease flare. Based on one of our prospective trials designed to determine whether ANCA titer and/or the presence or absence of CD19-expressing B cells could predict relapses, it was possible to adapt the time of RTX reinfusion to those parameters and to treat AAV patients in remission with less RTX (three infusions, i.e., 1,500 mg) versus 5 (2,500 mg). In contrast to previous results, that study showed that ANCA titer and ANCA positivity or negativity were not reliable predictors of relapses.
Semin Respir Crit Care Med. 2018;39(4):504-510. © 2018 Thieme Medical Publishers