What happened, in summary

A 58-year-old never-smoker was diagnosed in December 2018 after headaches and dizziness led to discovery of three brain lesions. Surgery on the largest lesion showed metastatic lung adenocarcinoma, and testing identified a KIF5B-RET fusion with negative PD-L1 expression. Imaging showed a left upper-lung mass with extensive nodal disease, making this Stage IV lung cancer. She received cisplatin and pemetrexed plus stereotactic radiation to brain and lung lesions and initially responded. After progression in 2019, she entered a clinical trial with cabozantinib, then moved to pralsetinib in January 2020. Pralsetinib controlled the cancer for about 3 years, although pneumonitis required steroids, dose interruptions and reductions, and limited progression was treated with additional stereotactic radiation. In May 2023, new lung and multiple brain lesions appeared. She switched to selpercatinib. After 3 months, brain imaging showed a response and lung disease was stable. Treatment remained ongoing after 8 months, more than 5 years after her original diagnosis.