Abstract
OBJECTIVES: Janus kinase inhibition (JAKi) has been proposed as a treatment for idiopathic inflammatory myopathies to target increased interferon signalling. Predominantly retrospective reports have demonstrated effectiveness of JAKi in refractory JDM. However, JAKi remains an off-label treatment for JDM and there may be variation in use worldwide. An international survey was conducted to investigate approaches to JAKi for JDM. METHODS: The Childhood Arthritis and Rheumatology Research Alliance (CARRA) JDM Therapeutics workgroup and core members of the Paediatric Rheumatology European Society (PReS) JDM working party devised an electronic survey to assess the use of JAKi in JDM. CARRA and PReS members were invited by e-mail to complete the survey. RESULTS: There were 229 respondents (18%), with 50% from the USA and 29% from Europe. One hundred and fifty had used JAKi for over 450 patients with JDM; among them, 77% noted clinical improvement in most or all patients and 17% reported side effects. The highest ranked perceived barriers to JAKi use were lack of clinical data and inability to obtain insurance approval. The highest ranked clinical indications for starting JAKi were refractory skin disease, refractory muscle disease, inability to wean steroids and intolerance to other steroid-sparing agents. CONCLUSION: Paediatric rheumatologists use JAKi off-label for refractory JDM. Most providers noted clinical improvement in their patients. Barriers to JAKi use include lack of clinical data and insurance coverage. Clinical trials are needed to provide better data on the efficacy and safety of JAKi.