WASHINGTON, DC USA (UroToday.com) - This report by Dr. Kurt Miller and colleagues suggests that the number needed to treat (NNT) with denosumab to prevent one skeletal-related event is five.
Denosumab is a fully human monoclonal anti-RANKL antibody. It was superior to zoledronic acid (ZA) in preventing skeletal-related events (SREs) in a randomized trial of prostate cancer patients with bone metastases. The NNT is a widely used method of expressing the benefit from a particular intervention. The NNT quantifies the benefit of a treatment by describing how many patients or patient-years of treatment are needed to prevent 1 undesirable event (in this case 1 SRE) or achieve 1 beneficial outcome.
The trial was randomized, double-blinded, and a double-dummy study including eligible castrate-resistant prostate cancer patients with bone metastases. They were randomized to receive either subcutaneous denosumab 120 mg (N = 950) or intravenous ZA 4 mg (N = 951) every 4 weeks. Supplemental calcium≥500 mg and vitamin D ≥400 IU were recommended for all patients. The NNT for denosumab compared with ZA was calculated using first and subsequent SREs and was reported in patient-years. This describes the benefit of treatment regardless of treatment duration. Denosumab reduced the risk of SREs by 18% vs. ZA; P = 0.008. Seven hundred eighty SREs occurred in 1,045 patient-years in the denosumab arm compared with 943 SREs in 996 patient-years in the ZA treatment arm. On average, compared with ZA, the NNT analysis demonstrates that treatment of 5 patients with denosumab would prevent an additional SRE (first or subsequent) per year.
He concluded that the low NNT for each SRE prevented suggests relatively high therapeutic efficacy for denosumab in men with prostate cancer and bone metastases compared to ZA.
Presented by Kurt Miller, et al. at the American Urological Association (AUA) Annual Meeting - May 14 - 19, 2011 - Walter E. Washington Convention Center, Washington, DC USA
Reported for UroToday by Christopher P. Evans, MD, FACS, Professor and Chairman, Department of Urology, University of California, Davis, School of Medicine.