Lutetium (177Lu) chloride is a radioactive compound used for the radiolabeling of pharmaceutical molecules, aimed either as an anti-cancer therapy or for scintigraphy (medical imaging).

[5][6] It is an isotopomer of lutetium(III) chloride containing the radioisotope 177Lu, which beta decays with a half-life of 6.64 days.

[5] It is used for the radiolabeling of carrier molecules specifically developed for reaching certain target tissues or organs in the body.

[5] 177Lu has been used with both small molecule therapeutic agents (such as 177Lu-DOTATATE) and antibodies for targeted cancer therapy[9][10] Medicines radiolabeled with 177Lu chloride must not be used in women unless pregnancy has been ruled out.

[7] In September 2024, the CHMP adopted a positive opinion, recommending the granting of a marketing authorization for the product Theralugand, a radiopharmaceutical precursor.