New drug combo shows promise for rare childhood muscle disease

Copied word for word from the study's registry entry, so the wording is the study team's rather than ours.

Inclusion Criteria: * Patient aged 3-18 years with new-onset juvenile dermatomyositis, according to the ENMC 2018 dermatomyositis classification criteria * Muscle weakness at MMT and/or CMAS (MMT \< 74 and/or CMAS \< 45) * Seropositivity or vaccination for chickenpox * For patients of childbearing age (following menarche) : Negative βHCG and effective method of contraception (sexual abstinence, hormonal contraception, intrauterine device or hormone-releasing system, cap, diaphragm or sponge with spermicide, condom) until the 7 days after administration of the last dose of Baricitinib * Informed consent form signed by the patient or child' s parents Patient affiliated to a social security regime Exclusion Criteria * Amyopathic dermatomyositis (without muscle weakness) * Inability to be treated by oral way or to take pills * Previous treatment with JAK inhibitor * Previous treatment of JDM with immunosuppressive drugs or biologics other than corticosteroids. Previous treatment with prednisone was allowed for no more than 1 month. * Previous history of cancer * Live vaccine within the 4 weeks before starting baricitinib therapy * Current, or recent (\< 4 weeks prior to baseline) of active infections according to investigator appreciation, but necessarily, including HBV, HCV, HIV, tuberculosis. * Positive blood CMV PCR * Creatinine clearance \< 40 ml/min * Lymphocytes \< 0,5x109 cell/L and Neutrophils \< 1x109 cell/L * Hemoglobin \< 8 g/dL * Symptomatic herpes herpes simplex infection within 12 weeks prior to inclusion * History of thrombosis or considered at high risk of venous thrombosis by the investigator * Presence of severe JDM-related involvements: cardiovascular (requiring vasopressive drug and/or intensive care unit), respiratory (requiring oxygen and/or intensive care unit), gastrointestinal (requiring abdominal surgery). * History of severe non-related JDM involvement: cardiovascular, respiratory, hepatic, gastrointestinal, endocrine, hematological, neurological or neuropsychiatric disorders or any other serious and/or instable illness that, in the opinion of the investigator, could constitute an unacceptable risk, when taking baricitinib. * Actual or in project of pregrancy and breast-feeding until the 7 days after administration of the last dose of Baricitinib * Patient on AME (state medical aid) * Participation in another interventional study involving human participants or being in the exclusion period at the end of a previous study involving human participants