Bone treatments: What to use and when

Spinal cord compression, pathological fracture and other skeletal-related events (SREs) feature prominently in patients with metastatic castration-resistant prostate cancer (mCRPC). The bisphosphonate, zoledronate, is widely, though not universally, regarded as a standard treatment to reduce the risk of SREs in these patients. However, new drugs are emerging suggesting that we may soon be able to offer a better standard of care for the prevention of SREs and metastatic bone pain

During a Special Symposium, held on Sunday Sep. 28th at ESMO 2012, on the medical treatment of advanced prostate cancer, Dr Chris Parker, Consultant Clinical Oncologist at the Royal Marsden Hospital NHS Foundation Trust, Sutton, UK, reviewed data for the various existing and emerging bone treatments for prostate cancer and provided his expert opinion regarding how we can best use these agents to improve overall survival (OS) and quality of life (QoL) and to delay SREs and bone metastases.

Dr Parker began his presentation by commenting on the lack of survival benefit observed with older bone-targeted agents such as zoledronate and clodronate, and the lack of difference in OS observed between zoledronate and denosumab, an inhibitor of receptor activator of nuclear factor kappa-B (RANK) ligand.

Various agents, including zoledronate and denosumab, appear to delay the development of SREs, and the newer agents, enzalutamide and abiraterone, also provide benefit in this setting. However, data from earlier this year showed that the bone-targeted alpha-emitter radium-223 is the first agent to improve OS (median OS of 14.9 months versus 11.3 months; HR 0.695; 95% CI: 0.581–0.832, p=0.0007), delay SREs (HR 0.64; 95% CI: 0.52–0.78, p<0.001) and improve QoL (FACT-P total score: 27 versus 18, p< 0.05) versus placebo in patients with mCRPC, suggesting that it may be a suitable option for both non-chemotherapy and post-chemotherapy patients with mCRPC.