Sirolimus leads to rapid and sustained clinical improvement of motor deficits in a patient with inclusion body myositis

Abstract

Background and purpose: To provide further evidence for sirolimus, a mammalian target of rapamycin inhibitor, as a treatment strategy for patients with inclusion body myositis (IBM). Methods: We acquired longitudinal clinical data and immunological assessments of CD8+ T-cell subsets in peripheral blood for evaluation of potential anti-inflammatory treatment effects of sirolimus. Results: Therapy with sirolimus 2 mg/day by mouth led to rapid and sustained clinical improvement of motor symptoms for an observation period of more than 1 year. Treatment was well tolerated, with no occurrence of adverse effects. We did not observe a meaningful alteration of CD8+ T-cell subsets in our patient after 9 and 12 months compared to baseline. Conclusions: The significant and persistent clinical improvement highlights the use of sirolimus as a potential treatment option in patients with IBM. In light of the lack of immunological treatment effects observed for cytotoxic CD8+ T cells, further studies should investigate the potential myoprotective effects of sirolimus.