Intravenous immunoglobulin and prednisone vs. prednisone in newly diagnosed myositis: a double blind randomized clinical trial

Who can take part

• Adult patients (≥ 18 years)
• IIM diagnosis accordiging to diagnostic criteria: - dermatomyositis, - antisynthetase syndrome, - Immune mediated necrotizing myopathy, - overlap/non-specific myositis, including polymyositis
• Disease duration <12 months
• Minimal disability defined as at least 10% loss on Manual Muscle Testing (MMT) and abnormal scores on two other Core Set Measures (CSMs) of the international Myositis Assessment and Clinical Studies (IMACS) group
• Signed informed consent

Who cannot take part

• Immunosuppressive medication or immunomodulatory treatment within the last 3 months (e.g. azathioprine, methotrexate, mycophenolate mofetil, tacrolimus, cyclophosphamide, cyclosporine, IVIg, biologicals, Janus kinase inhibitors, plasmapheresis). Exceptions to abovementioned exclusion criteria: • Patients are eligible for inclusion if there is no clinical evident response (as carefully judged by the treating physician at a screening visit) to prior treatment with: • High dosed glucocorticoids, such as dexamethasone (e.g. 40 mg per day up to 4 days) or intravenous methylprednisolone (e.g. 1000 mg daily for three days), within 1 week prior to screening visit. • Daily dosed prednisone 1 mg/kg, or equivalent, used for up to 2 weeks prior to screening visit. • Treatment with biologicals or other immunosuppressive or immunomodulatory treatment when meeting all of the following criteria: o Stable dose for the last 6 months o The biological or other immunosuppressive or immunomodulatory treatment has been approved for a non-muscular condition (e.g. hematological condition, eczema) o The biological or other immunosuppressive or immunomodulatory treatment is not known to induce inflammatory myopathy
• A known malignancy, which is likely to interfere with outcome assessment
• Conditions that are likely to interfere with: o Compliance (legally incompetent and/or incapacitated patients are excluded), or, o Evaluation of efficacy (e.g. due to severe pre-existing disability as a result of any disease other than myositis or due to a language barrier)
• Related to IVIg: o History of thrombotic episodes within 10 years prior to enrolment o Known allergic reactions or other severe reactions to any blood-derived product o Known IgA deficiency and IgA serum antibodies o Pregnancy or trying to conceive o Use of nephrotoxic medication
• Severe muscle weakness (i.e. bedridden, not able to walk, severe dysphagia requiring a nasogastric tube, or symptomatic respiratory muscle weakness (respiratory symptoms in combination with a forced vital capacity below 50% of predicted in upright position)) necessitating more intensive treatment than standard glucocorticoids