特発性炎症性筋疾患治療薬

Therapeutic Strategies for Idiopathic Inflammatory Myopathies

特発性炎症性筋疾患（idiopathic inflammatory myopathy：IIM）は封入体筋炎を除き，免疫治療で治療可能な疾患である。副腎皮質ステロイド治療（高用量プレドニゾロン内服，メチルプレドニゾロンパルス追加）を軸として2週間程度で効果判定を繰り返す。効果不十分の場合，アザチオプリン，タクロリムス，メトトレキサートなどの免疫抑制薬を追加し，その効果が表れるまで免疫グロブリン大量静注療法を行う。それでも治療抵抗性を示す場合は，リツキシマブなどの生物学的製剤を導入して寛解を目指す。病勢がコントロールできたらプレドニゾロンをはじめとする治療薬を漸減していく。

Abstract

Almost all types of idiopathic inflammatory myopathy (IIM) are treated by immune-modulating therapies. Corticosteroids, such as prednisolone and methylprednisolone, are used as first-line therapy for IIM. When the symptoms cannot be sufficiently improved, immunosuppressive agents, such as azathioprine, methotrexate, or tacrolimus, should be administered approximately two weeks after starting corticosteroid therapy. Moreover, intravenous immunoglobulin is recommended for severe cases at the same time as starting immunosuppressive agents. If these therapies do not improve symptoms, biologics, such as rituximab, should be introduced. Once IIM is controlled with immuno-modulating therapies, the drugs should be gradually tapered to avoid exacerbating the symptoms.