
The U.S. Food and Drug Administration (FDA) has cleared Fusion Pharmaceuticals' investigational new drug applications for two tumor therapy agents, actinium-225 FPI-2059 (FPI-2059) and the corresponding imaging analog indium-111 FPI-2058 (FPI-2058).
FPI-2059 is an alpha therapy designed to use a small molecule to target and deliver actinium-225 to tumor sites expressing neurotensin receptor 1, which is a protein that is overexpressed in multiple solid tumor cancers such as colorectal, pancreatic, gastric, neuroendocrine differentiated prostate, head and neck squamous cell carcinoma, and Ewing sarcoma.
Fusion plans to initiate a phase I clinical trial in patients with solid tumors expressing neurotensin receptor 1 that will focus on six solid tumor indications, it said.
















![A 53-year-old patient (patient number four) with a recurrent pituitary adenoma with extension of a cystic component of disease to the medial temporal lobe apparent on MRI (contoured in blue), and extension of disease to the left sphenoid bone and orbital apex apparent on [68Ga]Ga-DOTA-TATE (contoured in yellow).](https://img.auntminnie.com/mindful/smg/workspaces/default/uploads/2026/04/pituitary-tumor.QGsEnyB4bU.jpg?auto=format%2Ccompress&fit=crop&h=112&q=70&w=112)



