To investigate a new therapeutic strategy , with rapid corticosteroid dose tapering and limited cyclophosphamide ( CYC ) exposure , for older patients with systemic necrotizing vasculitides ( SNVs ; polyarteritis nodosa [ PAN ] , granulomatosis with polyangiitis [ Wegnener 's ] [ GPA ] , microscopic polyangiitis [ MPA ] , or eosinophilic GPA [ Churg-Strauss ] [ EGPA ] ) .