Abstract
Lung adenocarcinoma remains a leading cause of cancer mortality globally. While immune checkpoint inhibitors (ICIs) have improved outcomes in advanced non-small cell lung cancer (NSCLC), their efficacy in patients with acquired epidermal growth factor receptor (EGFR) T790M mutations following multiline therapy is poorly defined. This case report describes a 52-year-old Asian female never-smoker diagnosed with stage IIIA lung adenocarcinoma. She underwent lobectomy and received multiple lines of therapy. Initial genetic testing showed no EGFR T790M mutation, but subsequent testing after multiline treatment confirmed its acquired presence. Following multiline therapeutic failure, the patient received immunotherapy with cadonilimab (a PD-1/CTLA-4 bispecific antibody). This intervention resulted in disease control, and the patient achieved 9.4 months of progression free survival (PFS). This case suggests that immunotherapy with cadonilimab could be a potential consideration for advanced NSCLC harboring acquired EGFR T790M mutation post-multiline therapy.