FPI-2119

FPI-2119 is an investigational fibroblast activation protein (FAP)-targeted alpha-therapeutic (TAT) being developed by Fusion Pharmaceuticals, a subsidiary of AstraZeneca. The drug consists of a small molecule ligand with high affinity for FAP, conjugated to the alpha-emitting radioisotope Actinium-225 ($^{225}$Ac) via a proprietary linker and chelator. FAP is a cell-surface glycoprotein that is highly overexpressed on cancer-associated fibroblasts (CAFs) within the tumor microenvironment of most epithelial cancers, while remaining largely absent in healthy adult tissues. By targeting FAP, FPI-2119 delivers potent, short-range alpha radiation directly to the tumor stroma, inducing lethal double-stranded DNA breaks in both CAFs and nearby tumor cells through a bystander effect. This approach aims to overcome the limitations of traditional beta-emitting radiopharmaceuticals by providing higher linear energy transfer and more localized cytotoxicity. FPI-2119 is currently being evaluated in Phase 1 clinical trials for the treatment of various FAP-expressing solid tumors.

Other names

225Ac-FPI-2119