Upadacitinib for Refractory Anti-melanoma Differentiation-Associated Gene 5 Antibody-Positive Dermatomyositis-Related Interstitial Lung Disease

We report a 54-year-old man with recurrent anti-melanoma differentiation-associated gene 5 (MDA5) antibody-positive dermatomyositis (DM)-associated interstitial lung disease (ILD) who was refractory to intensive triple therapy with high-dose glucocorticoids, tacrolimus, and intravenous cyclophosphamide. After relapse following treatment discontinuation, he developed worsening respiratory symptoms, elevated ferritin and Krebs von den Lungen-6 (KL-6) levels, and progressive ILD on computed tomography. Despite the reintroduction of triple therapy, his condition deteriorated. Upadacitinib was initiated at 15 mg/day and later escalated to 30 mg/day. Subsequently, respiratory symptoms improved, oxygen therapy was discontinued, inflammatory biomarkers declined, and radiologic findings markedly improved. Infectious complications, including bacteremia, cellulitis, and cytomegalovirus reactivation, were successfully managed with close monitoring. This case suggests that upadacitinib may be an effective add-on therapy for refractory anti-MDA5 antibody-positive DM-associated ILD when conventional intensive treatment is insufficient.