As treatment of refractory idiopathic inflammatory myopathies (IIM) has been challenging, there is growing interest in assessing new therapies that target various pathways implicated in the pathogenesis of IIM. In the largest clinical trial to date, rituximab was studied in adult and juvenile myositis, but the primary outcome was not met despite 83 percent of subjects with refractory myositis meeting the definition of improvement. The U.S. Food and Drug Administration (FDA) has recently granted approval to Octagam 10% immune globulin intravenous (IVIg), for the treatment of adult dermatomyositis based on impressive results from a double-blind placebo-controlled trial. Anti-tumor necrosis factor (anti-TNF) utility in IIM is not recommended and recent reports suggest this therapy may induce systemic autoimmune disease including myositis. Further, anti-IL6 therapy cannot be recommended as a recent trial of tocilizumab failed to reach its primary endpoint.

Further studies are needed to assess the role of newer therapies such as abatacept (inhibition of T cell co-stimulation), sifalimumab (anti-IFNα), Janus kinase [JAK] inhibitors, apremilast (phosphodiesterase 4 inhibitor), and KZR-616 (selective inhibitor of the immunoproteasome) given their biological plausibility and encouraging recent small-case series results. The future of IIM therapy will depend on exploring biomarkers implicated in the etiopathogenesis of IIM, improvements in myositis classification based on serological and histopathological features, and well-designed controlled clinical trials using validated consensus outcome measures.

由于难治性特发性炎症性肌病 (IIM) 的治疗一直具有挑战性，因此人们越来越关注评估针对 IIM 发病机制中涉及的各种途径的新疗法。在迄今为止最大的临床试验中，利妥昔单抗在成人和青少年肌炎中进行了研究，但尽管 83% 的难治性肌炎患者符合改善的定义，但并未达到主要结果。根据一项双盲安慰剂对照试验的令人印象深刻的结果，美国食品和药物管理局 (FDA) 最近批准 Octagam 10% 免疫球蛋白静脉注射 (IVIg) 用于治疗成人皮肌炎。不推荐在 IIM 中使用抗肿瘤坏死因子（抗 TNF），最近的报告表明这种疗法可能会诱发全身性自身免疫性疾病，包括肌炎。更远，

需要进一步研究来评估新疗法的作用，例如阿巴西普（抑制 T 细胞共刺激）、西法木单抗（抗 IFNα）、Janus 激酶 [JAK] 抑制剂、阿普斯特（磷酸二酯酶 4 抑制剂）和 KZR-616。免疫蛋白酶体的选择性抑制剂），因为它们的生物学合理性和最近的小病例系列结果令人鼓舞。IIM 治疗的未来将取决于探索与 IIM 发病机制有关的生物标志物、基于血清学和组织病理学特征的肌炎分类改进，以及使用经过验证的共识结果测量的精心设计的对照临床试验。