188Re-Etidronate (188Re-HEDP) is a therapeutic agent for bone metastases treatment. It is under development in China and in Iran. It is available in India for the indication radiosynovectomy.
188Re-HEDP like all phosphonate derivatives has a high affinity for hydroxyapatite crystals which form the inorganic structure of the bone tissue. 188Re-HEDP is therefore indicated for bone metastases treatment in primary and metastatic bone tumors. Dose per patient is in the range 80 to 100 mCi.
188Re-Etidronate is under Phase III clinical trial development in China. Results from a clinical trial performed in Germany in 2009 showed that post-treatment overall survival could be improved from 4.5 to 15.7 months by multiple-injection bone-targeted therapy when compared with a single injection. In other words, this molecule is not only a pain palliation treatment but has a large benefit for the patient by prolonging life and reducing pain.