<br>        Inclusion Criteria:<br><br>          1. Subjects with diagnosis of definite or probable DM according to the Bohan and Peter<br>             criteria.<br><br>          2. Subjects under treatment with corticosteroids and/or maximally 2 immune-suppressants<br>             and being on stable therapy for at least 4 weeks.<br><br>          3. Subjects with active disease, assessed and agreed upon by an independent adjudication<br>             committee.<br><br>          4. Manual Muscle Testing-8 (MMT-8) score <142, with at least 2 other abnormal Core Set<br>             Measures (CSM) (Visual Analogue Scale [VAS] of patient global activity =2 cm,<br>             physician's global disease activity =2 cm, extra-muscular activity =2 cm; at least one<br>             muscle enzyme >1.5 times upper limit of normal, Health Assessment Questionnaire<br>             =0.25).<br><br>          5. Males or females = 18 to < 80 years of age.<br><br>          6. Voluntarily given, fully informed written consent obtained from subject before any<br>             study-related procedures are conducted.<br><br>          7. Subject must be capable to understand and comply with the relevant aspects of the<br>             study protocol.<br><br>        Exclusion Criteria:<br><br>          1. Cancer-associated myositis, defined as the diagnosis of myositis within 2 years of the<br>             diagnosis of cancer (except basal or squamous cell skin cancer or carcinoma in situ of<br>             the cervix that has been excised and cured and at least 5 years have passed since<br>             excision).<br><br>          2. Evidence of active malignant disease or malignancies diagnosed within the previous 5<br>             years (including hematological malignancies and solid tumors) or breast cancer<br>             diagnosed within the previous 10 years.<br><br>          3. Subjects with overlap myositis (except for overlap with Sjögren's syndrome),<br>             connective tissue disease associated DM, inclusion body myositis, polymyositis or<br>             drug-induced myopathy.<br><br>          4. Subjects with immune-mediated necrotizing myopathy with absence of typical DM rash.<br><br>          5. Subjects with generalized, severe musculoskeletal conditions other than DM that<br>             prevent a sufficient assessment of the subject by the physician.<br><br>          6. Subjects who have received IgG treatment within the last 6 months before enrolment.<br><br>          7. Subjects who received blood or plasma-derived products (other than IgG) or plasma<br>             exchange within the last 3 months before enrolment.<br><br>          8. Subjects starting or planning to start a physical therapy-directed exercise regimen<br>             during the trial.<br><br>          9. Cardiac insufficiency (New York Heart Association III/IV), cardiomyopathy, significant<br>             cardiac dysrhythmia requiring treatment, unstable or advanced ischemic heart disease.<br><br>         10. Severe liver disease, E.g. hepatitis or cirrhosis.<br><br>         11. Severe kidney disease (creatinine 1.5 times above the upper limit of normal).<br><br>         12. Known hepatitis B, hepatitis C or HIV infection.<br><br>         13. Subjects with a history of deep vein thrombosis within the last year prior to study<br>             enrollment or pulmonary embolism ever.<br><br>         14. Body mass index =40 kg/m2.<br><br>         15. Medical conditions whose symptoms and effects could alter protein catabolism and/or<br>             IgG utilization (e.g. protein-losing enteropathies, nephrotic syndrome).<br><br>         16. Known IgA deficiency with antibodies to IgA.<br><br>         17. History of hypersensitivity, anaphylaxis or severe systemic response to<br>             immuno-globulin, blood or plasma derived products or any component of Octagam 10%.<br><br>         18. Known blood hyperviscosity, or other hypercoagulable states.<br><br>         19. Subjects with a history of drug abuse within the past 5 years prior to study<br>             enrollment.<br><br>         20. Subjects unable or unwilling to understand or comply with the study protocol.<br><br>         21. Participating in another interventional clinical study with investigational treatment<br>             within 3 months prior to study enrollment.<br><br>         22. Women who are breast feeding, pregnant, or planning to become pregnant, or are<br>             unwilling to apply an effective birth control method while on study.<br>