Eosinophilia associated with nintedanib therapy

Nintedanib (Ofev) is a widely used antifibrotic agent approved for idiopathic pulmonary fibrosis and other fibrosing interstitial lung diseases, with a known side effect profile that includes gastrointestinal symptoms and hepatotoxicity. However, immune-mediated eosinophilia has not previously been associated with its use. We describe the case of a 69-year-old man recently diagnosed with pulmonary fibrosis who developed marked eosinophilia and transaminitis shortly after initiating treatment with Nintedanib. An extensive evaluation excluded infectious, autoimmune, and alternative drug-related etiologies. Remarkably, both the eosinophilia and liver enzyme abnormalities resolved promptly following the discontinuation of Nintedanib. This case represents, to our knowledge, the first reported instance of Nintedanib-associated eosinophilia, raising the possibility of a delayed hypersensitivity reaction.