“…A previous retrospective study by our group showed that patients aged 65 years or older who were diagnosed as having systemic necrotizing vasculitis (SNV; polyarteritis nodosa [PAN], granulomatosis with polyangiitis [Wegener's] [GPA], microscopic polyangiitis [MPA], or eosinophilic GPA [Churg‐Strauss] [EGPA]) had poorer outcomes than their younger counterparts, mainly because they developed more frequent and/or serious adverse events (SAEs; 68% versus 13%) while receiving conventional therapy . Several other groups have reported similar findings . Therefore, it is a common recommendation or practice to diminish, by up to one‐third, the dose of the most potent induction immunosuppressant, e.g., cyclophosphamide (CYC), for patients aged 65 years or older .…”