Ruxolitinib Treatment in Inclusion Body Myositis

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A Phase II/III Randomized, Double-blind, Placebo-controlled, Multicenter Study to Determine the Efficacy and Safety of Ruxolitinib in the Treatment of Subjects with Inclusion Body Myositis (IBM) IBM is the most frequent idiopathic immune myopathy (IIM) over age 45, pathologically characterized by the combination of intramuscular inflammation and degenerative features. It differs from other IIMs by its chronic evolution and refractoriness to common immunomodulatory drugs leading to marked disability and poor quality of life. Histological and molecular analyses of muscle biopsies from IBM patients showed intense muscular type II interferon (IFNγ) signature, stronger than observed in other IIMs. In vitro and in vivo experimental studies showed that IFNγ exerts myosuppressive effects through JAK/STAT pathway activation mimicking the degenerative features observed in IBM, and that these effects can be prevented by JAK-inhibitor ruxolitinib. Hypothesis/Objective : Ruxolitinib could be an effective therapy for IBM. Objective is to evaluate its therapeutic effects in IBM. Method : Comparative, multicenter, randomized, parallel-group, superiority, placebo-controlled, double-blind, phase 2 trial. 60 IBM patients able to walk during at least 6mn will be randomized in two groups (30/group) and received either ruxolitinib 15mgx2/d or placebo during 1 yr. Evaluation includes 6MWT, muscle strength quantification, functional scales, respiratory functional test and muscle MRI.