LAUSR

Osimertinib, the third generation of epidermal growth factor receptor (EGFR) tyrosine kinase inhibitors, responds well to advanced non–small-cell lung cancer (NSCLC) with the EGFR T790M mutation. However, resistance to osimertinib would inevitably occur. We report a case of an advanced NSCLC patient after osimertinib resistance who was successfully treated by high-dose furmonertinib (AST2818) at 160 mg. The patient initially received the GCP regimen for 11 months and displayed partial response. The patient received osimertinib 80 mg at the time of progression with a stable clinical and radiological response lasting only 7 months. Subsequently, she was commenced on furmonertinib 160 mg once daily. After 2 weeks of furmonertinib, the patient’s tumor was markedly smaller on a follow-up chest CT scan, and her respiratory symptoms also improved. What shocked us was that after a month’s re-examination of the cranial MRI, the intracranial lesions wholly disappeared. This report provides a case of the successful rescue of osimertinib-resistant NSCLC patients by oral administration of high-dose furmonertinib 160 mg daily, providing a new treatment option for osimertinib-resistant patients.