VIENNA—Radium-223, a novel investigational medication, improves overall survival and time to first skeletal-related event, with a highly favorable safety profile, in castration-resistant prostate cancer (CRPC) patients with bone metastases, according to findings presented at the European Society for Medical Oncology 2012 Congress.
Moreover, radium-223 preserves quality of life (QOL), with better functioning and well-being, compared with placebo.
Radium-223 is a first-in-class alpha-emitter. It targets bone metastases with high-energy, very short range (less than 100 µm) alpha particles. The interim analysis of ALSYMPCA study compared radium-223 chloride and placebo in CRPC patients with bone metastases receiving best standard of care. The interim analysis showed that the drug improved overall survival (OS), with a 30.5% reduction in risk of death.
Chris Parker, MD, a consultant clinical oncologist with The Royal Marsden NHS Foundation Trust, Sutton, United Kingdom, and colleagues reported updated survival, QOL, and safety data from ALASYMPCA. Eligible patients in this trial had previously received or refused docetaxel or were docetaxel ineligible. Investigators randomized patients to receive radium-223 chloride (50 kBq/kg IV) or placebo every four weeks for six weeks.
The updated analysis included all enrolled patients prior to crossover who had been assessed for effects of radium-223 on the primary endpoint of OS and secondary endpoints that included skeletal-related events (SREs), QOL, and safety. The investigators assessed QOL with the Functional Assessment of Cancer Therapy—Prostate (FACT-P) and EuroQoL (EQ-5D) instruments. The updated analysis looked at 921 patients (614 treated with radium-223 chloride and 307 who received placebo). The mean age of the patients was 70 years and 94% were Caucasian.
The time to first SRE was six months longer with radium-223 compared with placebo. Patients treated with radium-223 reported significantly greater well-being in terms of physical, emotional, and functional parameters, prostate cancer score, and total score, and significantly better QOL (EQ-5D) scores compared with placebo at week 16. The drug improved QOL response rate compared with placebo (27% vs. 18%). Moreover, radium-223 was better at preserving QOL compared with placebo as shown by FACT-P total scores. The updated analysis demonstrated that radium-223 significantly prolonged OS by 3.6 months compared with placebo, which translated into a significant 30.5% reduction in risk of death.
The agent was very well tolerated, with a low incidence of myelosuppression (2.2% grade 3/4 neutropenia; 6.3% grade 3/4 thrombocytopenia).
“We found that radium-223 not only improves overall survival of men with metastatic CRPC, but that it also improves quality of life,” Dr. Parker said. “Given that most men with metastatic CRPC die within a few years, maintaining a good quality of life is extremely important.”