ANCA-associated vasculitides are rare diseases, that are heterogeneous and potentially organ- and life-threatening, and require multidisciplinary treatment involving vasculitis experts. They are characterised by inflammation of the small vessels, which is why in principle any organ can be affected. The subtypes of AAV include:
While most of the original recommendations referred to AAV in general, separate recommendations have now been formulated for GPA/MPA and EGPA based on more recent data.1
Among other things, the EULAR working group recommends biopsies and ANCA tests (PR3-ANCA and MPO-ANCA) to make the initial diagnosis of ANCA-associated vasculitis. Another novelty of the updated recommendations is a consensus definition of different disease activities (active disease, remission, relapse and refractory disease instead of the previous subdivision into severe/not severe or generalised/non-generalised).2
The organisation also recommends an initial high-dose glucocorticoid surge in combination with rituximab or cyclophosphamide for remission induction in life-threatening or organ-threatening GPA or MPA. Rituximab is preferred for relapsing disease.1 Glucocorticoid doses should be gradually reduced, within 4 to 5 months to a target level of 5 mg prednisolone equivalents per day, to reduce the risk of infection.
Avacopan (a selective C5a receptor antagonist) may be considered in combination with rituximab or cyclophosphamide as part of a strategy to reduce glucocorticoid consumption in GPA or MPA. For patients with relapsed or refractory EGPA, the Task Force recommends the use of mepolizumab.3
For induction of remission in non-organ or non-life-threatening GPA or MPA, treatment with a combination of glucocorticoids and rituximab is recommended, although methotrexate or mycophenolate mofetil may be considered as an alternative to rituximab.1
The multidisciplinary working group emphasises that the recommendations are not intended as a "one size fits all" strategy due to the range of possible multi-organ involvement. Organ manifestations such as severe renal failure, myeloperoxidase (MPO)-ANCA-associated interstitial lung disease, bronchial/subglottic stenosis, orbital tumours, severe ENT pathologies, cardiac involvement in EGPA, central nervous system disease or vasculitic neuropathies require specific pharmacological and non-pharmacological interventions.1
The authoring group concludes with a classification of the limitations. Although much has happened in the last 10 years and many new randomised clinical trials have been incorporated into the current guideline update, the data situation remains thin due to the relative rarity of ANCA-associated vasculitis and the authors acknowledge that some recommendations had to be made on the basis of low-quality evidence.1