The utility of antineutrophil cytoplasmic antibody (ANCA) measures in patients with a confirmed diagnosis of ANCA-associated vasculitis (AAV) to monitor disease activity or predict recurrence remains debatable, however recent research shows that rituximab-treated individuals may play a role. For this research, scientists included all patients with active vasculitis and positive proteinase 3 (PR3)–ANCA who began a 2-year course of rituximab for induction of remission at Addenbrooke’s Hospital between January 2011 and January 2016. Common department practice includes 6 g of rituximab given over 2 years, concomitant corticosteroids (0.5–1.0 mg/kg) tapered over 3 months, and discontinuation of oral immunosuppressive medications at the time of the first rituximab dosage. Electronic patient records were used to collect clinical and laboratory data retrospectively.

In the study, 57 individuals with current PR3-ANCA positive were enrolled. The average period of follow-up was 59 months. With a median period of 14 months, PR3-ANCA negativity was reached in 25 patients (44%). Clinical remission was attained in 53 individuals (93%) in a median of three months. During follow-up, 24 (45%) of the 53 patients who achieved remission reverted, with a median duration to recurrence of 36 months after remission. PR3-ANCA–negative status and a 50% reduction in PR3-ANCA from baseline (as time-varying covariates) were both associated with a longer time to relapse (PR3-ANCA–negative status: hazards ratio, 0.08 [95% CI, 0.01–0.63, p = 0.016]; 50% reduction in PR3-ANCA: hazards ratio, 0.25 [95% CI, 0.18–0.99, p = 0.046]). Obtaining and sustaining PR3-ANCA negative following rituximab was linked to a longer duration of remission.