Ab0677 treatment of Idiopathic Inflammatory Myopathies – A Single Centre Experience

Abstract

BackgroundThere is no consensus or recommendations for the treatment of idiopathic inflammatory myopathies (IIM).ObjectivesWe explored how we treated incipient IIM patients in our secondary/tertiary rheumatology centre.MethodsWe retrospectively included cases with IIM diagnosed between January 2010 and June 2018, who were followed at least 6 months. The remission inducing treatment and the treatment at the last follow-up were recorded.ResultsDuring the 102-month period we identified 102 IIM cases (71.6% female, median (IQR) age 62.7 (52.2–72.1) years): 27.5% dermatomyositis, 22.5% anti-synthetase syndrome, 14.7% myositis in an overlap syndrome, 13.7% immune mediated necrotizing myopathy, 11.5% polymyositis, 6.9% cancer associated myositis, 2.9% inclusion body myositis (IBM), 1% unspecified myositis. 94 (92.2%) patients received glucocorticoids (GC), 18/94 (17.6%) as monotherapy. The remaining 81 (79.4%) were treated with additional immunomodulatory agents (Table 1), most commonly methotrexate. In addition to therapy presented in Table 1, 13 (12.7%) also received human immunoglobulins (IVIG), one (1%) received plasma exchange therapy.Of the 8 (7.8%) cases who were not treated with GC 3 received methotrexate, 1 rituximab, and 4 no additional treatment (1 paraneoplastic polymyositis received chemotherapy, 2 IBM, 1 mild polymyositis in elderly, multimorbid patient).In the first 6 months following diagnosis, 11 patients died (3 due to infection, 2 as a consequence of IIM, 1 due to haemorrhagic shock, 5 of unknown causes), and 5 were lost to follow-up. The remaining 86 patients were followed for a median (IQR) 37.7 (20.2–62.6) months. At last follow-up 49 (57%) patients were still receiving GC, 8 (9.3%) in monotherapy. 9 (10.5%) cases were off GC and other maintenance treatment. Maintenance treatment at last follow-up is presented in Table 2. Treatment was changed in 13 (15.1%) patients (due to progression of pulmonary involvement in 3, active myositis in 4, pulmonary involvement progression and active myositis in 1 and due to intolerance to medication in 6 cases). In addition to therapy presented in Table 2, 2 (2.3%) patients received IVIG (1 concurrently with rituximab and mycophenolic acid due to recalcitrant anti-synthetase syndrome and 1 due to IBM complicated with dysphagia).Table 1Induction treatment of idiopathic inflammatory myopathy Type of treatment N (%) Cyclophosphamide; median dose (range)23 (22.5); 6 (2–12) gMethotrexate43 (42.2)monotherapy30 (69.8)+ cyclosporine a8 (18.6)+ cyclosporine a and rituximab4 (9.3)+ chloroquine1 (2.3)Rituximab monotherapy4 (3.9)Azathioprine3 (2.9)Mycophenolic acid3 (2.9)Cyclosporine a monotherapy1 (1.0)Table 2Maintenance treatment of idiopathic inflammatory myopathy Type of treatment N (%) Methotrexate35 (40.7)monotherapy20 (57.1)+ cyclosporine a11 (18.6)+ rituximab2 (5.7)+ chloroquine2 (5.7)Azathioprine monotherapy13 (15.1)Rituximab monotherapy3 (3.5)Mycophenolic acid15 (17.4) monotherapy13 (86.7) + tacrolimus1 (6.7) + rituximab1 (6.7)Cyclosporine a1 (1.2)Tocilizumab*1 (1.2...