Phase III data support efficacy of denosumab in preventing skeletal events in men with metastatic prostate cancer

New analyses of data from the phase III study establishing the superiority of denosumab (XGEVA) to zoledronic acid (Zometa) for preventing skeletal-related events in men with bone metastases from castrate-resistant prostate cancer provide further evidence of the therapeutic value of the novel bone-targeted agent.

Key Points

The NNT values were calculated using data on total SREs and patient-years of drug exposure from the denosumab and placebo-controlled zoledronic acid pivotal trials and showed that denosumab had favorably low NNTs for preventing a first SRE compared with zoledronic acid (NNT=10); multiple SREs compared with zoledronic acid (NNT=5); and a first SRE compared with placebo (NNT=3).

He explained that an NNT of 10 comparing denosumab with zoledronic acid for preventing a first SRE indicates that 10 patients would need to be treated with denosumab instead of zoledronic acid for 1 year to prevent one additional SRE.

"Results of the published phase III trial demonstrate denosumab was superior to zoledronic in preventing SREs, significantly reducing the risks of a first on-study SRE and multiple SREs by 18%. However, NNT provides another clinically useful comparison of the relative benefits of two treatments," Dr. Miller said.

To put the NNT data in perspective, Dr. Miller cited results from an analysis of data from the European Randomized Study of Screening for Prostate Cancer that showed 48 men would need to be treated after screening to prevent one prostate cancer death.