Rituximab in refractory idiopathic inflammatory myopathies and antisynthetase syndrome: personal experience and review of the literature.

In this paper, we report our experience with the use of rituximab (RTX) in the treatment of refractory idiopathic inflammatory myopathies (IIM) and review the literature on this topic. Six adult patients (5 female, 1 male) with active IIM, as defined by persistent proximal muscle weakness, elevated serum muscle enzymes, muscle magnetic resonance imaging, electromyographic and histological abnormalities, refractory to at least one immunosuppressant, including methotrexate, were treated with RTX (1,000 mg twice, 2 weeks apart). Patients were regularly followed up for serial assessment of muscle strength by manual muscle test 8 and creatine kinase serum levels. Three patients were affected with polymyositis (PM) and three with anti-t-RNA synthetase syndrome (ASS). A complete B-cell depletion was observed in all patients by 3 months after RTX. A significant clinical improvement was observed in 5 out of 6 cases 6 months after RTX. Only one mild infusion reaction and one case of Herpes zoster infection were observed. A review of the literature to find all the available cases of refractory patients affected with IIM from 1980 to 2012, using the PubMed database, was performed. We were able to find 27 papers, 18 on PM and dermatomyositis and 9 on ASS, including 88 and 40 patients, respectively. A significant improvement was observed in 80% of patients overall and the drug was well tolerated in the majority of cases. In conclusion, RTX can be considered a therapeutic option in refractory IIM.