From the Guidelines
Intravenous Immunoglobulin (IVIG) is the recommended next step in treatment for myositis patients who have failed initial immunosuppressive therapy. The typical IVIG regimen consists of 1 to 2 g/kg of ideal body weight, usually given over 2 consecutive days, once a month for 1 to 6 months 1. Treatment should be initiated with close monitoring for adverse effects such as headache, thrombotic events, and aseptic meningitis. It is essential to check the serum IgA level before administering IVIG because IgA deficiency may lead to fever, infusion reactions, and/or severe anaphylaxis 1.
Key Considerations
- The dosage of IVIG may be adjusted based on the patient's response and tolerability, with some patients requiring higher doses or more frequent infusions 1.
- Premedication with acetaminophen and diphenhydramine is recommended to minimize infusion reactions, and adequate hydration should be maintained throughout treatment.
- For patients who respond inadequately to IVIG, alternative options include rituximab (1000 mg IV given twice, two weeks apart) or cyclophosphamide (typically 500-750 mg/m² monthly) 1.
- IVIG works by neutralizing pathogenic autoantibodies, inhibiting complement activation, and modulating inflammatory cytokines, making it particularly effective for refractory myositis cases 1.
Monitoring and Adjustments
- After 3-6 months of therapy, clinical response should be assessed to determine whether to continue treatment.
- If improvement occurs, consider gradually extending the interval between infusions to 6-8 weeks while maintaining the same total dose.
- Regular monitoring of laboratory parameters, including complete blood counts and liver function tests, is necessary to detect potential adverse effects of IVIG therapy 1.
From the Research
Treatment Options for Myositis After Failed Immunosuppression
- The next step in treatment for myositis after failed immunosuppression is often the use of Intravenous Immunoglobulin (IVIG) 2.
- IVIG has been shown to be effective in patients with dermatomyositis, polymyositis, and necrotizing autoimmune myopathy (NAM) who have not responded to corticosteroids or other immunosuppressants 2, 3.
- The exact mechanism of action of IVIG in myositis is not fully understood, but it is thought to involve the reduction of anti-myosin antibody and the blocking of complement deposition 4.
Efficacy and Safety of IVIG
- Studies have demonstrated the efficacy of IVIG in reducing disease activity and improving symptoms in patients with myositis 2, 3, 4.
- IVIG has also been shown to be a safe and well-tolerated treatment option, with few adverse reactions reported 5.
- However, IVIG can be resource-intensive and may require frequent hospital visits, which can be a burden for some patients 5.
Alternative Treatment Options
- Subcutaneous immunoglobulin (SCIG) has been proposed as an alternative to IVIG, offering the potential for home-based therapy and reduced resource needs 5.
- SCIG has been shown to be effective in maintaining disease control and reducing the need for corticosteroids in patients with myositis 5.
- Other treatment options, such as rituximab and tacrolimus, may also be considered for patients with myositis who have not responded to IVIG or other therapies 2.
Ongoing Research and Future Directions
- The use of IVIG in myositis is being further investigated in ongoing clinical trials, including the TIME IS MUSCLE study, which aims to evaluate the efficacy of early add-on IVIG in patients with newly diagnosed myositis 6.
- The results of these studies will help to inform treatment decisions and optimize outcomes for patients with myositis.