Actinium Ac 225 PSMA-R2

**Semantic type:** Indicator, Reagent, or Diagnostic Aid|Pharmacologic Substance

**Definition:** A radioconjugate composed of PSMA-R2, a human prostate-specific membrane antigen (PSMA)-targeting ligand, conjugated to the alpha-emitting radioisotope actinium Ac 225, with potential antineoplastic activity against PSMA-expressing tumor cells. Upon intravenous administration of 225Ac-PSMA-R2, the PSMA-R2 moiety targets and binds to PSMA-expressing tumor cells. Upon binding, PSMA-expressing tumor cells are destroyed by a cytotoxic dose of alpha radiation. PSMA, a tumor-associated antigen (TAA) and type II transmembrane protein, is expressed on the membrane of prostatic epithelial cells and overexpressed on the majority of prostate tumor cells.

**Synonyms:** - 225Ac-PSMA-R2 - 225Ac-labeled PSMA-R2 - 225AcPSMA-R2 - Ac225-PSMA-R2 - Actinium (225Ac) PSMA-R2 - Actinium-225 PSMA-R2 - [225Ac]Ac-PSMA-R2