According to Dr. Aggarwal, treatment decisions should be based on the category of IIM; the specific phenotype of disease, as indicated by myositis-specific autoantibodies; the nature of organ involvement (e.g., skin disease, arthritis, interstitial lung disease); and a consideration of potential toxicities and side effects from treatment.
He noted that intravenous immunoglobulin (IVIG) is the only clearly evidence-based treatment that has been approved for use in IIM by the U.S. Food & Drug Administration.
In the ProDERM study, Dr. Aggarwal and colleagues enrolled patients with dermatomyositis on a stable dose of standard therapy (e.g., mycophenolate mofetil or methotrexate, glucocorticoids and hydroxychloroquine). These patients were then randomized to receive either 2 g/kg of IVIG or placebo every four weeks for 16 weeks. Patients who showed clinical deterioration in this period were switched to the alternative treatment and, at week 16, all patients on placebo and those without clinical deterioration on IVIG received 2 g/kg of IVIG every four weeks for 24 weeks. The researchers then measured the proportion of responders in each group with at least minimal improvement in the total improvement score (i.e., a composite response criteria) without deterioration at two consecutive visits up to week 16 and found that 79% of patients receiving IVIG and 44% of patients receiving placebo met this end point, respectively. Treatment-emergent adverse events were comparable in the IVIG and placebo groups.5
In Sum
The talk was enlightening and served to show both how far the field of rheumatology has come in better understanding IIM, yet how far we have to go to best treat these diseases across the world.
Jason Liebowitz, MD, completed his fellowship in rheumatology at Johns Hopkins University, Baltimore, where he also earned his medical degree. He is currently in practice with Skylands Medical Group, N.J.
References
- Bohan A, Peter JB. Polymyositis and dermatomyositis (first of two parts). N Engl J Med. 1975 Feb 13;292(7):344–347.
- Bohan A, Peter JB. Polymyositis and dermatomyositis (second of two parts). N Engl J Med. 1975 Feb 20;292(8):403–407.
- Leclair V, Lundberg IE. New myositis classification criteria–What we have learned since Bohan and Peter. Curr Rheumatol Rep. 2018 Mar 17;20(4):18.
- Barsotti S, Dastmalchi M, Notarnicola A, et al. Performance of the new EULAR/ACR classification criteria for idiopathic inflammatory myopathies (IIM) in a large monocentric IIM cohort. Semin Arthritis Rheum. 2020 Jun;50(3):492–497.
- Aggarwal R, Charles-Schoeman C, Schessl J, et al. Prospective, double-blind, randomized, placebo-controlled phase III study evaluating efficacy and safety of octagam 10% in patients with dermatomyositis (“ProDERM Study”). Medicine (Baltimore). 2021 Jan 8;100(1):e23677.
