Immune checkpoint inhibitor esophagitis with excellent response to oral viscous budesonide

• Management of ICI esophagitis is not well defined in current guidelines • First reported use of oral viscous budesonide for ICI esophagitis • Rapid clinical, endoscopic, and histologic response to oral budesonide • Remission achieved without systemic corticosteroids or biologics • Highlights need for tailored GI toxicity management in cancer care Immune checkpoint inhibitors (ICIs) are increasingly utilised in the treatment of advanced malignancies. ICIs can result in a wide array of immune-related adverse events of which gastrointestinal toxicities are common. We present a 52-year-old female with severe dysphagia and heartburn despite proton pump inhibitor therapy whilst receiving pembrolizumab for breast cancer. A diagnosis of ICI esophagitis was made following gastroscopy with esophageal specimens when combined with the patients’ symptoms and immunotherapy exposure. Pembrolizumab was discontinued and she was treated with oral viscous budesonide which has proven efficacy in eosinophilic esophagitis but is not well established in treatment of ICI-related esophagitis. There was an impressive response to oral viscous budesonide, and this avoided the need for systemic immunosuppression. This is the first case in the literature to describe the presentation, treatment protocol and outcome for a patient treated with oral viscous budesonide for ICI-related esophagitis.