Promising results from two phase 2 studies of 12-week duration in anti-MPO- and anti-PR3-positive ANCA-associated vasculitis suggest that avacopan is well tolerated [29,30] and that its use in combination with either cyclophosphamide or rituximab may result in comparable clinical effectiveness (as assessed by the BVAS) with that of the standard-of-care glucocorticoid-containing regimen, with more rapid onset of disease control measured at week 4, as well as improved renal outcomes and quality of life [29]. This evidence concerns the gene MPO and anti-neutrophil cytoplasmic antibody-associated vasculitis.