Anca-associated vasculitis treatment

ANCA-associated prophylaxis or treatment of vasculitis and / or recurrence inhibitors, as well as provide methods of treatment using the same. Eicosapentaenoic acid, pharmaceutical compositions containing at least one selected from the group consisting of pharmaceutically acceptable salts and esters, as an active ingredient. The pharmaceutical compositions may, recurrence inhibition of ANCA-associated vasculitis, chronic form ANCA-associated vasculitis treated, are useful for the prevention and treatment of rapidly progressive nephritic syndrome (RPGN).