Myositis specific autoantibody subtypes are associated with response to Janus kinase inhibitors in patients with juvenile dermatomyositis
Myositis specific autoantibody subtypes are associated with response to Janus kinase inhibitors in patients with juvenile dermatomyositis

Myositis specific autoantibody subtypes are associated with response to Janus kinase inhibitors in patients with juvenile dermatomyositis

Rheumatology (Oxford). 2025 May 24:keaf214. doi: 10.1093/rheumatology/keaf214. Online ahead of print.

ABSTRACT

OBJECTIVES: To evaluate the efficacy and safety of Janus kinase inhibitors (JAKi) in a monocentric series of patients with juvenile dermatomyositis (JDM) and to identify factors associated with the achievement of clinically inactive disease (CID).

METHODS: Single-centre retrospective study of 39 JDM patients treated with JAKi fot at least 6 months. The proportion of patients achieving CID within 6 months after initiation of JAKi was assessed using the PRINTO criteria and the Skin Disease Activity Score. Type 1 interferon (IFN) gene signature, serum IFN-α and IFN-β protein titres were measured as potential response biomarkers.

RESULTS: 39 patients with JDM were included. Partial or complete CID was achieved in 32/39 (82%) patients after 6 months of treatment. In responders, the mean steroid dose decreased from 1 to 0 mg/kg/d (p= 0.001) and all other medications were withdrawn. In multivariable analysis, the presence of anti-TIF-1γ antibodies was the only factor at JDM onset associated with the absence of CID (p< 0,001. A significant decrease in the median Type 1 IFN score and serum IFN- α from the diagnosis of JDM to the 6-months follow-up was observed only in patientswith CID. JAKi-related adverse events consisted of infections in 9 patients (including 5 herpes zoster infections) and weight gain in 3 patients.

CONCLUSIONS: JAKi induced CID in the majority of new-onset and refractory JDM patients, except in a subset of patients with refractory TIF-1γ positive JDM. Overall tolerance was acceptable. These results need to be validated in a larger prospective international cohort study.

PMID:40411753 | DOI:10.1093/rheumatology/keaf214