Response to cyclophosphamide and rituximab therapy in idiopathic inflammatory myopathies: A single center experience

Abstract

Aim of the workTo evaluate the clinical response to cyclophosphamide (CYC), and rituximab (RTX) following CYC regarding muscle power and creatine kinase (CK) level changes, and the ability to manage cardiac and bulbar affection in dermatomyositis (DM) and polymyositis (PM) patients. Patients and methodsTwenty two idiopathic inflammatory myopathies (IIM) patients: 14 (63.6%) DM and 8 (36.4%) PM were categorized into CYC group (n = 17) received only CYC, and RTX group received RTX following refractory CYC (n = 5). History taking and clinical examination were done, and Medical Research Council Sum Score (MRC-SS) and CK were evaluated at baseline visit, by end of monthly CYC, and 18 months after CYC or RTX. Improvement of cardiac affection or bulbar manifestations was checked. ResultsPatients were 16 females and 6 males (F:M 2.7:1) and mean age was 34.9 ± 14.9 years. The patients were followed up for 7.7 ± 4.3 years. MRC–SS increased in (CYC group) and in (RTX group) (p < 0.001, and p = 0.018 respectively). CK levels decreased significantly in CYC group (p < 0.001) but not in RTX group. MRC-SS changes in males, females, DM, PM patients were (p = 0.007, p < 0.001, p < 0.001, p = 0.006 respectively), and CK changes (p = 0.17, p < 0.001, p < 0.001, p = 0.006 respectively). The two DM cardiac patients and the three PM patients with bulbar manifestations in (RTX group) showed improvement in their extra-muscular manifestations. ConclusionCYC can be an effective drug in the treatment of IIM muscle affection. RTX may be promising for refractory myositis, cardiac and bulbar manifestations, so these patients should be a target for its early administration.