Baricitinib could improve the prognosis of anti-MDA5 antibody positive dermatomyositis associated interstitial lung disease

Currently, there are only a few effective treatments for anti-melanoma differentiation-associated gene 5 antibody (anti-MDA5) positive dermatomyositis (DM)-associated interstitial lung disease (ILD). The aim of this study was to evaluate the efficacy and safety of baricitinib in patients with MDA5 + DM-ILD. The study was a retrospective cohort design that evaluated patients with MDA5 + DM-ILD who had received or not received baricitinib. Clinical symptoms, laboratory data, and survival were compared in the two groups. Thirty-nine patients with MDA5 + DM-ILD who received baricitinib were included in the study. After baricitinib therapy, 31 patients (79.5%) had a clinical improvement that included Gottron’s sign (p < 0.001), heliotrope rash (p < 0.001), and dyspnea (p = 0.003). The median HRCT score decreased from 115 to 97.5 (p < 0.001), while the FVC improved significantly (76.44% vs. 90.73%, p < 0.001). In addition, serum ferritin levels (739.9 ng/ml vs. 56.3 ng/ml, p < 0.001) and lactate dehydrogenase (LDH) levels (313 U/L vs. 233 U/L, p = 0.003) decreased significantly. Notably, lymphocyte counts increased significantly, CD4 + T cells (354 cells/µl vs. 663 cells/µl, p < 0.001), and CD8 + T cells (180 cells/µl vs. 449 cells/µl, p < 0.001). Furthermore, the glucocorticoid dose reduced significantly from 40 mg daily to 10 mg daily (p < 0.001). Compared with the control group, the baricitinib group had a greater six-month survival (87.2% vs. 70%, p = 0.047). While first-line baricitinib showed a superior survival rate compared to conventional therapy (84.6% vs. 52.9%, p = 0.046). This study indicates that Baricitinib is a potential therapeutic for MDA5 + DM-ILD, reducing LDH and ferritin, ameliorating ILD progression, and improving survival, with first-line use may provide a significant survival advantage. However, larger prospective controlled studies are required to evaluate its efficacy. 1. This is the retrospective cohort study of baricitinib in the treatment of MDA5 + DM-ILD. 2. Baricitinib improve clinical symptoms, reduce LDH and serum ferritin levels, and reduce ILD progression in MDA5 + DM. 3. Baricitinib could improve MDA5 + DM patients’ survival, with first-line use may provide a significant survival advantage.