thorium-227

Thorium-227 is a radioactive isotope and alpha-emitting radionuclide used as the payload in targeted radiopharmaceuticals for cancer therapy. Its primary application is in the form of targeted thorium-227 conjugates (TTCs), which consist of thorium-227 complexed to a chelator and covalently attached to a tumor-targeting monoclonal antibody or ligand. This enables highly selective delivery of potent alpha radiation directly to cancer cells while sparing healthy tissue. The mechanism of action involves emission of high linear energy transfer (LET) alpha particles that induce clustered double-stranded DNA breaks, leading to cell cycle arrest, apoptosis, and immunogenic cell death. Thorium-227-based therapies are being investigated for various solid tumors (e.g., ovarian cancer, hepatocellular carcinoma) and hematologic malignancies (e.g., CD22-positive non-Hodgkin’s lymphoma). The development of stable chelators such as 3,2-hydroxypyridinone has enabled efficient conjugation and clinical translation. Thorium-227 radiopharmaceuticals represent an emerging class within targeted alpha therapy with ongoing preclinical studies and early-phase clinical trials[1][2][3][4][5][6][7].

Other names

227ThTh-227Th227Th 227