The current study proposal aims to investigate the clinical practice variation of the initial use of avacopan for AAV patients in Europe. The study will describe patient characteristics and organ-specific clinical benefit of avacopan treatment in a unique, first-experience cohort of AAV patients. By studying the clinical practice variation of first-experience avacopan treatment, this study will be uniquely positioned to identify pivotal issues on the real-life implementation of avacopan treatment. These observational data can ultimately serve to address current knowledge gaps on avacopan treatment in AAV patients, improve the care and drug-access for AAV patients with avacopan treatment and generate new areas of research.

Objective: Analyse the clinical practice variation of the early access use of avacopan in real-world treated patients with ANCA-associated vasculitis.

Study design: Observational cohort study Study population: AAV patients treated with avacopan.

Main study parameters/endpoints:

• Describe physician's treatment indications for starting avacopan
• Describe AAV patients clinical characteristics
• Describe the concomitant treatment strategies employed with avacopan
• Describe clinical outcomes of avacopan treatment
• Investigate determinants of clinical benefit as well as non-response and/or relapse within the study cohort

Inclusion Criteria:

• Established diagnosis of GPA or MPA
• Treatment (initiation) with avacopan
• Informed consent for use of medical data

Exclusion Criteria:

• If there is no AAV disease activity present that can be supported by an objectifiable clinical measure or assessment
• If a subject is below 16 years old

A multicenter, non-interventional, longitudinal cohort study which will collect incident as well as prevalent AAV patients treated with an avacopan-based regimen. The cohort will include retrospective and prospective data capture on real-life management and outcomes.