Efficacy of rituximab in difficult to treatment patients with polymyositis

Abstract

Inflammatory myopathies are a heterogeneous group of diseases rarely encountered in clinical practice. They primarily involve the transverse striated muscles, and in some cases there is also extramuscular involvement of the skin, lungs, joints, esophagus, heart. Acute forms of myositis, which are the most common, are associated with viral diseases and usually resolve spontaneously. Chronic forms usually have a subacute onset and unknown etiology. The presence of different clinical phenotypes and courses is associated with diversity in autoantibody production. Historically, the treatment of refractory forms of polymyositis and dermatomyositis has undergone significant dynamics. Data from various studies have been published that show a significant reduction in the symptoms of inflammation, but unfortunately some of these disease-modifying treatments could not be established in rheumatology practice as sufficiently effective. Limiting factors are the retrospective nature of these studies, as well as different inclusion and exclusion criteria. However, in recent years, more and more data have emerged that present rituximab as one of the promising molecules for the treatment of patients refractory to conventional synthetic disease-modifying antirheumatic agents We present a clinical case of a 40-year-old Caucasian man with onset of the disease – fever, asthenodynamia, muscle pain and weakness, pericardial and pleural effusions. The patient was treated with glucocorticoids, methotrexate, pulse therapies with methylprednisolone and cyclophosphamide, as well as pulse therapy with intravenous immunoglobulins. Due to the temporary effect of the treatment and the relapse of the disease, the patient was started on mycophenolate mofetil therapy (instead of methotrexate). However, a new peak in disease activity was reported, necessitating resumption of pulse therapies with methylprednisolone and cyclophosphamide. Due to the refractory course of the disease, the patient was treated with rituximab after signed informed consent. A significant reduction in disease activity and a good clinical and therapeutic effect were reported.