Vipivotide tetraxetan
Vipivotide tetraxetan is a radiopharmaceutical precursor molecule used in targeted therapies for prostate cancer and other tumors expressing prostate-specific membrane antigen.
PSMA-617 is a high-affinity inhibitor of the peptidase activity of PSMA, with a Ki of 0.37 nM. It consists of a PSMA-targeting moiety conjugated to a high-affinity chelator for metal isotopes. Its strong binding affinity for PSMA allows precise targeting of cancer cells that overexpress this protein, especially in prostate cancer.
Vipivotide tetraxetan is used as a precursor in the synthesis of radiopharmaceuticals such as Lu-PSMA-617 and Ac-PSMA-617. In Lu-PSMA-617, vipivotide tetraxetan chelates the radioactive isotope lutetium-177, a β-emitter used in targeted radioligand therapy. In Ac-PSMA-617, it binds actinium-225, an α-emitter used in targeted alpha-particle therapy.
Chemistry
The compound's structure includes a PSMA-binding motif, a hydrophobic linker, and a DOTA chelator for radiolabeling.Nomenclature
Vipivotide tetraxetan is the International Nonproprietary Name and United States Adopted Name for the ligand-targeting and metal-chelating components, respectively, of the radiopharmaceutical drugs Lu-PSMA-617 and Ac-PSMA-617."Vipivotide" refers to the peptide-based targeting moiety that binds specifically to prostate-specific membrane antigen on prostate cancer cells. The suffix "tide" denotes the peptide nature of this moiety.
"Tetraxetan" refers to the chelator moiety, a chemical group that binds metal ions within the molecule. The name "tetraxetan" is derived from "tetraazacyclododecane tetra-acetic acid", a well-known macrocyclic chelator that securely holds the radioactive isotope in the drug. The "tetra-" prefix indicates the four nitrogen atoms in the macrocycle and the four acetic acid arms in the DOTA structure, while "xetan" is a standard suffix for chelators.