From: the 2014 ASCO GU Meeting

Abstract No: 35

Researchers have found in a randomized controlled trial of men with metastatic castration-resistant prostate cancer (mCRPC) the use of the treatment denosumab was superior to the more commonly used zoledronic acid (ZA) for reducing skeletal-related events (SRE). SREs are defined as a pathological fracture, surgery or radiation to the bone [including the use of radioisotopes], or spinal cord compression.

In the trial men with mCRPC who had at least one or more SRE and never received IV bisphosphonate were randomized to receive either denosumab 120 mg or IV ZA 4 mg (adjusted for creatinine clearance) every 4 weeks. Oral calcium and vitamin D supplements were also recommended.

This trial confirmed the previously reported result from other studies that fewer men who received denosumab than ZA had confirmed first SREs as well as additional multiple SREs.

The median (95% CI) estimate of time to first SSE for denosumab was not reached (28.8 mo, not estimable), and for ZA it was 24.2 (20.7, 30.2) mo (HR = 0.78 (0.66, 0.93) P = 0.01).

Denosumab reduced the risk of skeletal events in men with mCRPC regardless of endpoint definition as SRE or SSE. The risk of developing SSEs was reduced by up to 22% when comparing denosumab with ZA.

Take Home: Denosumab is superior to Zolendronic Acid. Despite this many physicans still use Zolendronic acid, probably because they are more familiar with it. Question your doctor if they recommend ZA and obtain a good explanation why not Denosumab.

J Clin Oncol 32, 2014 (suppl 4; abstr 35)
Author(s): Matthew R. Smith, Robert E. Coleman, Laurence Klotz, Kenneth B. Pittman, Piotr Milecki, Rachel Wei, Arun Balakumaran, Karim Fizazi; Harvard Medical School and Massachusetts General Hospital, Boston, MA; Weston Park Hospital, Sheffield, United Kingdom; University of Toronto, Toronto, ON, Canada; The Queen Elizabeth Hospital, Adelaide, Australia; Wielkopolskie Centrum Onkologii, Poznan, Poland; Amgen, Inc., Thousand Oaks, CA; Institut Gustave Roussy, University of Paris Sud, Villejuif, France

Clinical trial information: NCT00321620.

Joel T. Nowak, M.A., M.S.W.