Rhenium-188 based radiopharmaceuticals for treatment of liver tumours.

Rhenium-188 (188Re) is a high energy beta-emitter with a physical half life of 17 hours. Various 188Re based radiopharmaceuticals were developed to treat liver malignancies. The vast majority of studies focus on patients suffering from hepatocellular carcinoma (HCC). Most radiopharmaceuticals are based on Lipiodol as a vehicle for the rhenium-188. The radiopharmaceutical that was tested clinically in detail is the 188Re-HDD/Lipiodol, developed by the Seoul University. Clinical data derived from several phase I and II studies using 188Re-HDD/Lipiodol suggest an excellent tolerance in patients with Child-Pugh A cirrhosis. A shortcoming in some trials was the occasional low labelling efficiency of 188Re-HDD/Lipiodol. Some newer 188Re based radiopharmaceuticals claim to have consistent high labelling efficiencies, however clinical data for these compounds are scarce or lacking at this moment. Hopefully, phase I clinical data will become available for promising radiopharmaceuticals such as 188Re-SSS-Lipiodol, developed by the group of Rennes, in the upcoming years. In Dresden a very different approach is used. They labelled human serum albumin microspheres with high activities of 188Re. In a small group of patients with liver metastasis and a few HCC patients, treatment proved safe. In the present clinical field, 188Re-based radiopharmaceuticals will have to proof firmly their strength and reliability in large patient groups if they want to compete with the commercially available yttrium-90 microspheres.