<p>Outcomes after first relapse.</p>

All outcomes were evaluated descriptively. In the MMF-added group, MMF was initiated at a median of 0.4 months after the first relapse (interquartile range [IQR], 0.3–0.4 months; range, 0.3–0.5 months). The median age was 76 years (IQR, 73–81 years); 16 patients (94.1%) were MPO-ANCA-positive.

During a median follow-up of 28 months (IQR, 21–33 months), all patients achieved remission after post-relapse treatment intensification. No second relapse occurred in the MMF-added group, whereas three patients in the MMF-not-added group experienced a second relapse. Glucocorticoids were discontinued in all nine patients in the MMF-added group, whereas in the MMF-not-added group, all eight patients continued glucocorticoids while they were managed without MMF.

Severe infections requiring hospitalization occurred in none of the patients in the MMF-added group and in three patients in the MMF-not-added group. Because treatment allocation was non-randomized and post-relapse treatment strategies differed with respect to RTX scheduling, concomitant therapies, and physician-directed glucocorticoid tapering, the independent effect of MMF could not be determined. Therefore, these descriptive and hypothesis-generating findings warrant confirmation in future prospective studies.</p></div>