Radium-223 dichloride (Xofigo) has been approved as an intravenous radiotherapy for men with castration-resistant prostate cancer (CRPC) who have multiple osseous (bone) metastases. Most often, it is used in men who have too many metastases to treat with spot radiation.
Xofigo works by mimicking calcium that is attracted to bones. To be successful the drug must successfully circulate through out the body to be able to find all of the metastases. A recent study evaluated the ability of the intravenous introduction of the Xofigo to properly circulate through the body.
The researchers relied on the fact that Xofigo in addition to the therapeutic alpha radiation also generates photons that can be imaged with a conventional gamma camera. By using a gamma camera they were able to evaluated real-time the systemic circulation and also exclude Xofigo extravasation at the injection site.
The researchers imaged fifteen Xofigo administrations. They performed dynamic imaging of the chest before, during, and after the administration of the Xofigo. Both before and after administration of the Xofigo they made a static image of the intravenous access site.
The imaging of the chest confirmed a successful systemic administration early during the 1-minute injection period for all fifteen men. They also determined that there were no cases of Xofigo extravasation at the site of intravenous access.
This information confirms that the intravenous induction of Xofigo circulates in the chest and does not leak at the injection site. It does not provide us with any information about the circulation outside of the chest, areas that are often affected with osseous metastases.
Wright CL, Monk JP 3rd, Murrey DA Jr, Hall; Biomed Res Int. 2015;2015:324708.
Joel T. Nowak, M.A., M.S.W.