One of the newer drugs and one that has recently had great air play is the bone targeting radiopharmaceutical drug radium-223 or Xofigo. Currently, it is approved for men with castrate resistant prostate cancer with bone metastases.
The problem is that currently Xofigo is only approved for one round of treatment using 6 monthly infusions. Given its success, the question we are now asking is if additional dosing would provide an even better result?
Bayer Pharmaceuticals currently has a number of clinical trials examining this type of question. In one of the small prospective studies looking at the impact of an additional 6 doses of radium-223 they found that of 44 men in the trial only 1 showed any signs of confirmed radiographic progression, or 43 didn’t have any additional progression.
This result is positive, but we still cannot say that there is a therapeutic benefit. This question is yet to be determined.
Additionally, Bayer is sponsoring a 3-arm study in which men are assigned to the standard dose for 6 doses, a higher dose for 6 doses, or the standard dose for 12 doses. They are also sponsoring a trial to see if men with both bone and soft tissue mets will benefit (currently having soft tissue mets is an exclusion to receiving radium-223). These trials should provide us with further insight and help provide us additional information about the potential of increasing the dosing of radium-223 (Xofigo) as well as expanding the FDA label in allow men with both soft and bone mets to receive the drug.