Favorable rituximab response in patients with refractory idiopathic inflammatory myopathies

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.

Efficacy and Safety of Rituximab in Korean Patients with Refractory Inflammatory Myopathies

“…Most of the patients did not receive additional immunosuppressive agents during the observational period except one patient who started MTX 6 weeks after RTX administration. Our data reveals that the long-term clinical efficacy of RTX may persist, which is similar to previous studies, 45 whereas reconstitution of peripheral blood B cell lineage occurs within a few months. 46 …”

Efficacy of Rituximab in Refractory Inflammatory Myopathy Associated With Coexistence of Behçet's Disease and Antiphospholipid Syndrome

“…In the largest trial of RTX in inflammatory myositis involving 195 patients, 83% had a clinical response and the mean dose of prednisone was significantly reduced. There are no solid data on other biologicals [2, 3] . According to these data, the authors considered RTX the most appropriate treatment for this patient.…”

Antisynthetase syndrome: A distinct disease spectrum

“…133,150,151 Increasing number of retrospective studies have shown benefit and safety of RTX in ILD associated with ASSD with reported objective improvement in PFT, ground-glass opacities and stability, or fibrosis on HRCT of chest. 100,138,139,[152][153][154][155][156][157][158][159][160] Those who had acute onset of ILD or had RTX within 12 months of disease onset had the best outcome. 139 In an open-label study of 10 patients with ASSD and refractory ILD, treatment with RTX resulted in a substantial steroid-sparing effect; clinically significant increase in FVC and/or DLCO was observed in 5 out of the 10 patients, stabilization in 4, and worsening in 1.…”