Important Clinical Applications of ¹⁸⁸Rhenium for Radionuclide Therapy

Abstract

Although established clinical utility is of key importance in choosing agents for radionuclide therapy, other key factors include costs and GMP availability of sterile, pyrogen-free, regulatory approved radiopharmaceuticals. No-carrier-added (NCA) ¹⁸⁸Rhenium(¹⁸⁸Re, 16.9 hour half-life; 155 keV gamma emission) is available on demand as ¹⁸⁸Re-perrhenate from saline elution of a ¹⁸⁸Tungsten/¹⁸⁸Rhenium(¹⁸⁸W/¹⁸⁸Re) generator. The availability and superb radionuclidic and chemical properties make ¹⁸⁸Re an excellent candidate for radionuclide therapy. This radioisotope is readily attached to a variety of targeting agents and also emits high energy beta particles (E_max 2.12 MeV) for therapy. Over the last 30 years the effectiveness of ¹⁸⁸Re for a variety of therapeutic applications has been established in multiple clinical studies. This overview provides a brief summary of clinical applications with ¹⁸⁸Re-labeled agents as an introduction to the detailed clinical discussions in the following papers. Although ¹⁸⁸Re-labeled radiopharmaceuticals for routine clinical use and accompanying reimbursement are not yet commercially available, several agents have been evaluated in clinical studies. In addition, a large number of ¹⁸⁸Re radiopharmaceutical agents have been developed and evaluated in pre-clinical studies over the last three decades. This review focuses on providing examples of ¹⁸⁸Re-labeled radiopharmaceutical agents which have entered late stage clinical use and have demonstrated good efficacy. These key applications include palliative treatment of skeletal metastases, intra-arterial therapy of liver cancer and post PTCA intravascular inhibition of arterial restenosis. Also, ¹⁸⁸Re radiopharmaceuticals had been developed and initially assessed for synovectomy and for marrow suppression. More recently, a unique device-based technology has entered clinical use for therapy of non-melanoma skin cancer using a ¹⁸⁸Re topical cream. Finally, ¹⁸⁸Re-antibodies are being developed for the potential therapy of infectious disease and this unique new therapeutic strategy is expected to enter clinical trials in the near future.