DR SARTOR: It’s really an interesting question, because it gets down into a mechanism that I think that we can wave our hands about either one.
So it is a bone-protective treatment in the sense that it does decrease skeletal-related events, defined clinically as radiation to bone surgery to bone pathologic fractures, spinal cord compression. But at the same time, it prolongs survival. And I believe that there is antitumor activity, but the interesting question to me is whether or not it’s direct antitumor activity or whether or not it might be altering the bone microenvironment in a way that it inhibits the future growth of the cancer.
And I’m really sort of agnostic here. I think that there’s a case to be made either way. And it’s an interesting agent that we have to learn a lot more about.
DR LOVE: Can I just ask, back to this issue about symptoms — and then I’ll ask Dan — have you had patients who had bone pain that got better on radium-223?
DR SARTOR: Yes. Yes. Unequivocally.
DR LOVE: So we’re just going to finish up on a couple more quick questions we’ve gotten from oncologists about this, Oliver, and then we’ll take our break. What about radium-223 chloride in other tumors with bone mets?
DR SARTOR: Studies underway. Initial data from breast cancer are provocative but preliminary.
DR LOVE: Who can give it?
DR SARTOR: It has to be done by someone licensed to administer radioisotopes. That’ll probably be either nuclear medicine or radiation oncology.
DR LOVE: Is calcium supplementation interaction a factor?
DR SARTOR: No.
DR LOVE: After a patient receives radium-223, can a bone lesion be treated with external beam irradiation?
DR SARTOR: Yes.