Early relapse under the LoVAS reduced-dose glucocorticoid regimen in ANCA-associated vasculitis: a single-center retrospective observational study.

To evaluate early relapse and other clinical outcomes in patients with microscopic polyangiitis (MPA) or granulomatosis with polyangiitis (GPA) treated with reduced-dose glucocorticoid (GC) regimens, with a focus on the LoVAS regimen in comparison with the PEXIVAS regimen. We conducted a retrospective single-center cohort study of consecutive patients with newly diagnosed or relapsing MPA or GPA treated between March 2022 and September 2025. Patients were classified into LoVAS or PEXIVAS groups if they adhered to the assigned reduced-dose GC regimens for at least 14 days. The primary outcome was time to first relapse. Secondary outcomes included time to GC withdrawal, time to serious adverse events, and cumulative GC exposure. Time-to-event outcomes were analyzed descriptively using Kaplan-Meier curves and log-rank tests and were interpreted as exploratory because of the small sample size and limited number of events. A total of 21 patients were included (LoVAS, n = 5; PEXIVAS, n = 16). Relapse occurred in 3/5 patients in the LoVAS group and 2/16 patients in the PEXIVAS group. In the LoVAS group, relapses occurred on days 21, 52, and 128 after treatment initiation. GC was withdrawn in 5/5 patients in the LoVAS group and 5/16 patients in the PEXIVAS group. Serious adverse events occurred in 3/5 patients in the LoVAS group and 7/16 patients in the PEXIVAS group. The median average daily prednisolone-equivalent dose was lower in the LoVAS group than in the PEXIVAS group: 3.06 mg/day versus 14.5 mg/day. These findings were interpreted descriptively because of the small sample size and limited number of events. These findings should be interpreted as hypothesis-generating and suggest that early relapse may occur in some patients treated with the LoVAS regimen in real-world practice. Further studies with larger cohorts and appropriate adjustment for confounding factors are needed.