NEW YORK, March 22, 2011 /PRNewswire/ -- A study in the prostate cancer space completed this week by ITG's Majestic Market Research reveals that Amgen's (Nasdaq: AMGN) Xgeva (a.k.a. denosumab, Prolia) is on track to achieve its blockbuster sales potential and is already stealing share from the leading agent for skeletal related events, Novartis' (NYSE: NVS) Zometa. As for Dendreon's (Nasdaq: DNDN) Provenge, the first FDA-approved therapeutic cancer vaccine, physicians are still clouded with uncertainty regarding whether/how they will incorporate the agent into their treatment paradigm once it finally becomes more widely available. The report entitled Event Pulse: Launches of Xgeva and Provenge examines how the recent launches of Amgen's Xgeva and Dendreon's Provenge are shaking things up in prostate cancer treatment practices. Amgen's denosumab first received approval for osteoporosis in June 2010 under the trade name Prolia. In November 2010, the agent received an approval for a second indication under the trade name Xgeva for the treatment of skeletal related events (SREs) in patients with bone metastases from solid cancer tumors. "On the heels of a modest launch for denosumab in osteoporosis, we are encouraged by several metrics from our unique data sets that indicate the drug is achieving much greater success in the oncology setting," said Karen Cundari, Assistant Vice President and lead healthcare analyst at ITG. The study shows that Xgeva has already been prescribed by 13% of prostate cancer specialists in ITG's exclusive oncology panel. By comparison, Prolia had only been prescribed by 2% of osteoporosis specialists at this point in its launch. Furthermore, the analysis reveals that Novartis' Zometa has already forfeited measurable market share to Xgeva in the prostate cancer setting. Despite the fact that Xgeva's cost of therapy is nearly double that of Zometa, survey respondents expressed enthusiasm for Xgeva's superior efficacy and relatively low-risk safety profile. Weighing all of those factors, surveyed physicians estimated that Xgeva utilization will grow to represent ~39% of SRE treatments administered to prostate cancer patients in their practices. At the same time, they anticipated that Zometa will continue to lose significant share and come to represent ~49% of SRE treatments. As for Provenge, the study assesses the drug's performance to date as well as the future appetite for Dendreon's product. The research indicates that Provenge has been prescribed by only 5% of specialists to date. Moreover, nearly two-thirds (64%) of Provenge non-users indicated the reason they have not prescribed the drug is because it is still unavailable at their facility. These findings reflect the fact that Provenge's launch has been hampered with serious supply issues, which are slated to be resolved in 2011. Cundari noted, "Dendreon may face continued headwinds even after supply of Provenge is ramped up. The Dendreon sales force will need to make a concerted promotional effort that focuses on clearly defining how the benefits of Provenge justify the cost." When asked about their future plans to prescribe the drug, 65% of Provenge non-users indicated they are either unsure or do not plan to prescribe the drug in the next year. When probed, surveyed physicians explained that Provenge's high cost and poor insurance access will be barriers to future adoption.