TOPLINE:

In patients with antineutrophil cytoplasmic antibody (ANCA)-associated vasculitis treated with rituximab, risk factors for relapse differed by treatment phase; musculoskeletal involvement was associated with increased odds of relapse during the maintenance phase, and elevated immune markers were linked to increased odds of relapse after treatment withdrawal.

METHODOLOGY:

• Researchers conducted a post hoc analysis of a trial to identify risk factors for relapse in 170 patients (median age, 59 years; 51% female) with ANCA-associated vasculitis who tested positive for anti-proteinase 3 or anti-myeloperoxidase antibodies and achieved remission after reinduction with rituximab.
• Patients who achieved remission by month 4 were randomly assigned to receive either rituximab (1000 mg at months 4, 8, 12, 16, and 20) or azathioprine (2 mg/kg/d from months 4 to 24, tapered off during months 24-27) as maintenance therapy. Patients were followed up for up to 48 months or until relapse occurred during the observational off-treatment phase.
• The main outcome was relapse, defined as the return or first appearance of disease activity before or at the next study visit (3- to 6-month intervals).
• Clinical characteristics, laboratory markers (including ANCA status and levels of CD19-positive B cells), and patient-reported outcomes were assessed at enrollment and at all study visits.
• The study focused on identifying predictors during the maintenance (months 4-24) and the off-treatment (months 24-48) phases separately.

TAKEAWAY:

• A total of 99 relapses were observed during follow-up: 46 during maintenance therapy and 53 during the off-treatment phase.
• During the maintenance phase, musculoskeletal involvement (odds ratio [OR], 2.8; 95% CI, 1.1-7.5; P = .038) was associated with increased odds of relapse, whereas treatment with rituximab (OR, 0.3; 95% CI, 0.2-0.7; P = .001) was associated with reduced odds of relapse in the multivariable model.
• In the off-treatment phase, higher levels of immunoglobulin A were associated with increased odds of relapse.
• Patients who received rituximab maintenance therapy experienced substantially increased odds of relapse at month 30.

IN PRACTICE:

“[A]mong patients with AAV [ANCA-associated vasculitis], markers of inflammation and immune reconstitution are associated with disease relapse within 3-6 months during the period of observation off treatment after completion of a regimen to maintain remission. These data support monitoring of these laboratory tests at regular intervals to help identify patients with AAV at risk for relapse after withdrawal of treatment,” the authors of the study wrote.

SOURCE:

The study was led by Ellen Romich, MD, Division of Rheumatology, University of Pennsylvania, Philadelphia. It was published online on December 18, 2025, in Arthritis & Rheumatology.

LIMITATIONS:

The clinical trial setting involved selectively enrolled patients. Defining the on-treatment and off-treatment phases may have been challenging. Missing data for some laboratory values, especially CD19 -positive B-cell measurements, limited the ability to include a single quantitative measure of B cells.

DISCLOSURES:

The study received funding from Arthritis Research UK (now Versus Arthritis), Roche/Genentech, and the Vasculitis Clinical Research Consortium, which was supported by the National Center for Advancing Translational Science and the National Institute of Arthritis and Musculoskeletal and Skin Diseases. The study was supported by the Penn Vasculitis Center. Some authors reported receiving funds, consulting fees, research support, holding stock options, or other ties with various pharmaceutical companies or organizations. One author reported having an immediate family member employed by a pharmaceutical company and holding shares in another company.

This article was created using several editorial tools, including AI, as part of the process. Human editors reviewed this content before publication.