Juvenile dermatomyositis (JDM) is a rare and severe paediatric-onset idiopathic inflammatory myopathy, associated with significant morbidity and mortality. The combination of corticosteroids and methotrexate (MTX) is recommended in new-onset JDM according to one randomized trial. However, in this trial, treatment failures were reported in 13/46 (28%) patients and severe JDM, (cutaneous or gastrointestinal ulceration, interstitial pulmonary disease, cardiomyopathy) were not taken into account. These data emphasize the need for a more efficient first-line treatment. Considering: 1) the strong implication of type IFN-I in the pathophysiology of JDM 2) the report of the efficacy and safety of JAK inhibitors (JAKis) (baricitinb, tofacitinib) in about 50 refractory DM patients, and 9 JDM, a trial which evaluates the efficacy and safety of baricitinib in combination with corticosteroids in new-onset JDM is warranted.
The MYOCIT study aims to evaluate the efficacy and safety of baricitinib in association with corticosteroids in new-onset patients with juvenile dermatomyositis (JDM) in a phase II trial with the objective to obtain a better efficacy than the conventional combination methotrexate (MTX) and corticosteroids over the 24 week study period. Thus, the investigators hypothesize that baricitinib could be used as a first line treatment in all forms of DMJ, including the most severe one, with a good safety profile.