213Bi-DOTA-substance P

213Bi-DOTA-substance P is a targeted alpha therapy (TAT) radiopharmaceutical being investigated for the treatment of recurrent glioblastoma multiforme (GBM). The drug consists of a modified version of the neuropeptide substance P, which serves as a high-affinity ligand for the neurokinin type 1 receptor (NK-1R), a G protein-coupled receptor that is highly overexpressed on the surface of GBM cells. This peptide is conjugated to the chelator DOTA (1,4,7,10-tetraazacyclododecane-1,4,7,10-tetraacetic acid) and labeled with the alpha-emitting radionuclide bismuth-213 (213Bi). Upon administration, the substance P moiety targets NK-1R-expressing tumor cells, delivering the 213Bi payload which emits high-energy alpha particles with a short range (approximately 50-80 micrometers). This localized radiation causes lethal double-strand DNA breaks in tumor cells while sparing adjacent healthy brain tissue. The therapy is typically administered locally via intracavitary or intratumoral injection using stereotactically inserted port-a-cath systems to bypass the blood-brain barrier and maximize tumor exposure.

Other names

[213Bi]Bi-DOTA-substance P213Bi-DOTA-substance P213Bi-DOTA-SP