Idiopathic Inflammatory Myopathies

Research into novel therapies for rare, immune-mediated inflammatory diseases (IMIDs) is limited due to small patient populations. Patients with Behçet's disease (BD), idiopathic inflammatory myopathy (IIM, also known as myositis) and IgG4-related disease (IgG4-RD) are treated with high-dosed glucocorticoids, methotrexate, azathioprine and mycophenolate mofetil, mostly for long periods of time with attendant risks of long-term toxicity, including infections. Therefore, there is an urgent need for new, more specific anti-inflammatory therapies such as targeted synthetic and biological disease-modifying antirheumatic drugs. Due to the role of type 1 interferon in both BD, IIM and IgG4-RD, JAK-STAT inhibition may be a promising treatment strategy in these conditions, because JAK1 is critical for the signal transduction of pro-inflammatory cytokine receptors. Previous research showed that JAK1 inhibition reduces activation of type 1 interferon-regulated proteins and key chemokines that control tissue inflammation.