Baricitinib for acute exacerbation in idiopathic interstitial pneumonias: A preliminary study using propensity score matching

Background and objective: Acute exacerbation of interstitial lung disease (AE-ILD) is a life-threatening complication for which there are only limited treatment options, with essentially no established treatment options. Janus kinase (JAK) inhibitors, such as baricitinib, have recently emerged as potential therapeutic candidates for severe and progressive forms of ILD. This study aimed to evaluate the efficacy and safety of baricitinib in patients with AE-ILD associated with idiopathic interstitial pneumonias (IIPs). Methods: This retrospective cohort study included patients with IIPs who experienced AE-ILD, and were admitted to a single tertiary care center. Patients treated with baricitinib (Dec 2022–Jun 2024) were compared with historical controls (Jan 2021–Nov 2022). Propensity score matching (PSM) was conducted using age, PaO₂/FiO₂ ratio, and fibrosis score. The primary outcome was overall survival; secondary outcomes included 90-day survival and adverse events. Results: After PSM, 17 patients were analyzed in each group. The 90-day survival rate in the baricitinib group (82.4%) was significantly higher than in the control group (52.9%, P = 0.049), while longer-term survival did not differ to a statistically significant extent. Baricitinib was well tolerated, with only mild adverse events observed. A trend toward improved 90-day survival was also noted with anti-fibrotic therapy administered during AE-ILD (P = 0.089). Conclusions: Baricitinib may improve short-term survival in AE-ILD and was well tolerated in the acute phase. Its dual JAK1/2 inhibition suggests both anti-inflammatory and antifibrotic potential. Further prospective studies are needed to confirm these findings and explore combination therapies.