• systemic vasculitis
• outcomes research
• granulomatosis with polyangiitis
• B cells

We read with great interest the article on ‘comparison of individually tailored versus fixed-schedule rituximab regimen to maintain ANCA-associated vasculitis remission: results of a multicentre, randomised controlled, phase III trial (MAINRITSAN2)’ by Charles and Terrier. 1 They have tried to address a crucial aspect of rituximab dose titration during remission maintenance of anti-neutrophil cytoplasmic antibody (ANCA)-associated vasculitis (AAV). The key message is that, although AAV relapse rates did not differ significantly among the two groups, the patients in the individually tailored group received fewer rituximab infusions. This outcome has a significant bearing on cost and drug-related side effects. However, certain aspects of this study require further clarification.

First, ‘the trial was designed to detect a 20% absolute between-arm …