The α-particle–emitting nuclide 225Ac has been coupled to prostate-specific membrane antigen (PSMA)–targeting ligands to successfully treat prostate cancers refractory to treatments with androgen deprivation, taxanes, and 177Lu-PSMA-617 (Pluvicto; Advanced Accelerator Applications), which is approved for treatment of patients with PSMA-positive metastatic castration-resistant prostate cancer in the United States (11–14). The gene discussed is FOLH1; the disease is prostate cancer.