Fernando Henrique Carlos de Souza1, Renata Miossi1, Júlio Cesar Bertacini de Moraes1, Eloisa Bonfá2, Samuel Katsuyuki Shinjo3. 1. Division of Rheumatology, Hospital das Clinicas HCFMUSP, Faculdade de Medicina, Universidade de Sao Paulo, Sao Paulo, Brazil. 2. Division of Rheumatology, Faculdade de Medicina FMUSP, Universidade de Sao Paulo, Sao Paulo, Brazil. 3. Division of Rheumatology, Faculdade de Medicina FMUSP, Universidade de Sao Paulo, Sao Paulo, Brazil. samuel.shinjo@gmail.com.
Abstract
BACKGROUND: Interpretation of rituximab efficacy for refractory idiopathic inflammatory myopathies (IIM) is hampered by the absence of a uniform definition of refractory myositis and clinical response. Therefore, rigorous criteria of refractoriness, together with a homogenous definition of clinical improvement, were used to evaluate rituximab one-year response. METHODS: A retrospective cohort study including 43 IIM (15 antisynthetase syndrome, 16 dermatomyositis, 12 polymyositis) was conducted. All patients had refractory disease (inadequate response to at least two immunosuppressives/immunomodulatories and no less than three months sequentially or concomitantly glucocorticoid tapering) criteria. Clinical/laboratory improvement at one-year was based on modified International Myositis Assessment & Clinical Studies Group (IMACS) core set measures. The patients received two infusions of rituximab (1 g each) at baseline, followed by repeated dose after 6 months. Baseline immunosuppressive therapy was maintained and glucocorticoid dose was tapered according to clinical/laboratory parameters. RESULTS: Five patients had side effects at the first rituximab application and were excluded. Therefore, 38 out of 43 patients completed the one-year follow up. Almost 75% of the patients attained clinical and laboratory response after one-year. A significant reduction in median glucocorticoid dose (18.8 vs. 6.3 mg/day) was achieved and 42% patients were able to discontinue prednisone. In contrast, young individuals and patients with dysphagia had a tendency to be non-responders to rituximab. No severe infections were observed. CONCLUSION: This study provides convincing evidence that rituximab is an effective and safe therapy for refractory IIM.
BACKGROUND: Interpretation of rituximab efficacy for refractory idiopathic inflammatory myopathies (IIM) is hampered by the absence of a uniform definition of refractory myositis and clinical response. Therefore, rigorous criteria of refractoriness, together with a homogenous definition of clinical improvement, were used to evaluate rituximab one-year response. METHODS: A retrospective cohort study including 43 IIM (15 antisynthetase syndrome, 16 dermatomyositis, 12 polymyositis) was conducted. All patients had refractory disease (inadequate response to at least two immunosuppressives/immunomodulatories and no less than three months sequentially or concomitantly glucocorticoid tapering) criteria. Clinical/laboratory improvement at one-year was based on modified International Myositis Assessment & Clinical Studies Group (IMACS) core set measures. The patients received two infusions of rituximab (1 g each) at baseline, followed by repeated dose after 6 months. Baseline immunosuppressive therapy was maintained and glucocorticoid dose was tapered according to clinical/laboratory parameters. RESULTS: Five patients had side effects at the first rituximab application and were excluded. Therefore, 38 out of 43 patients completed the one-year follow up. Almost 75% of the patients attained clinical and laboratory response after one-year. A significant reduction in median glucocorticoid dose (18.8 vs. 6.3 mg/day) was achieved and 42% patients were able to discontinue prednisone. In contrast, young individuals and patients with dysphagia had a tendency to be non-responders to rituximab. No severe infections were observed. CONCLUSION: This study provides convincing evidence that rituximab is an effective and safe therapy for refractory IIM.