At the recent European Multidisciplinary Cancer Congress in Stockholm, Dr Chris Parker from The Royal Marsden Hospital presented results of the phase 3 ALSYMPCA trial that showed both delayed time to first skeletal-related event (SRE) AND an overall survival (OS) benefit for those men with advanced prostate cancer taking radium-223 (Alpharadin). The real significance of this coming to you soon drug is that it will be the first bone treatment for advanced prostate cancer has shown any survival benefit. Not denosumab (Xgeva) or zoledronic acid (Zometa), the only currently approved bone treatments, have demonstrated any survival benefit.
Making the results of the trial more interesting, unlike the recent approved treatments, cabazitaxel (Jevtana) and abiraterone acetate (Zytiga), the trial included both men who had already been treated with chemotherapy (docetaxil) and men who had not been treated.
As Dr Parker mentioned in his presentation, radium-223, Could provide a new treatment option for the considerable population of men with bone metastases who may be too weak, too old or otherwise unable to take chemotherapy.
Dr Parker also said that he believes that combining radium-223 with abiraterone acetate (Zytiga) makes sense. This will need to be studied further.
Notwithstanding this excellent news, radium-223 still faces a number of issues, such as how to monitor the treatment as well as working out the optimal dose.
Since radium-223 is a weak alpha emitter and the radiation can be blocked by paper or glass, it will not require any special facility for its administration. However, it does require that the doctor have a radiopharmaceutical license, which means that community based oncologists and urologists in the United States will most likely have to refer patients to receive their injection at an approved facility where there is a nuclear medicine/radiology department or equivalent expertise. In Europe, this is less of an issue given most cancer patients are treated in outpatient clinics associated with hospitals, whereas in the US, the majority of patients are seen in the community setting.
Given the fact that in advanced prostate cancer that about 80% of the disease affects the bone, radium-223 is an exciting radiopharmaceutical that is likely to be “treatment changing” once approved.
Despite the many hurdles that still remain, radium-233 is clearly on fast track with the FDA. I have seen some optimistic estimates that we could have an approval next year. We’ll have to wait and see
Joel T Nowak, M.A., M.S.W.