Lutetium-177 1,4,7,10-tetraazacyclododecane-1,4,7,10-tetraacetic acid complex (177Lu-DOTA)

DOTA-chelated 177Lu (Lutetium-177) is a radiotherapeutic complex that serves as the cytotoxic component in various targeted radioligand therapies rather than being a biological target itself. It consists of the radioisotope Lutetium-177, a medium-energy beta emitter with a half-life of 6.647 days, securely held by the macrocyclic chelating agent DOTA (1,4,7,10-tetraazacyclododecane-1,4,7,10-tetraacetic acid) [1,5]. This complex is chemically conjugated to targeting vectors, such as peptides or small molecules, which exhibit high affinity for specific biomarkers overexpressed on cancer cells, most notably somatostatin receptors (SSTR) in neuroendocrine tumors and prostate-specific membrane antigen (PSMA) in prostate cancer [2,4]. Once the drug binds to its biological target, the Lutetium-177 isotope delivers localized ionizing radiation that induces lethal DNA damage, primarily through double-strand breaks, resulting in tumor cell death [3]. The short range of the beta particles helps limit damage to surrounding healthy tissue, while the accompanying gamma emission facilitates real-time biodistribution monitoring and personalized dosimetry [6]. Clinical use of this complex has significantly improved outcomes for patients with advanced, metastatic malignancies that are refractory to conventional treatments [4].

Other names

177Lu-DOTADOTA-177LuLutetium (177Lu) DOTALutetium-177 DOTA complexDOTA-chelated Lutetium-177

DOTA-chelated 177Lu acts as a radioactive payload within radioligand therapies. Lutetium-177 is a beta-emitting radioisotope with a maximum energy of 0.5 MeV and a mean tissue penetration range of approximately 0.67 mm [1]. When conjugated to a targeting ligand (such as a somatostatin analog or a PSMA binder) via the DOTA chelator, the complex is delivered to cells expressing specific surface receptors [2]. Upon binding and subsequent internalization, the 177Lu isotope undergoes beta decay, releasing ionizing radiation that causes single- and double-strand DNA breaks, leading to apoptosis in the target cell and adjacent tumor cells via the bystander effect [3]. It also emits low-energy gamma rays (113 keV and 208 keV), which allow for scintigraphic imaging and dosimetry [4].