Trends in the use of bone agents in metastatic cancer.

e20672 Background: Bone modifying agents have been shown to delay and/or prevent skeletal-related events for a range of cancers metastatic to the bone. Various studies have identified pamidronate, zoledronic acid, and denosumab as bone modifying agents, each of which confers clinical benefit. The convenience of administration and costs of these agents differ greatly. Administration spans vary from roughly 2 hours for IV pamidronate, 15 minutes for IV zoledronic acid, and minimal time for subcutaneous denosumab. The estimated cost for a single dose of pamidronate, zoledronic acid, and denosumab are $29, $890, and $1,712, respectively. Methods: All requests for pamidronate, zoledronic acid, and denosumab authorization submitted by practicing oncologists within southeast Florida were tabulated for 2010, 2011, and 2012. Comparisons for both frequency of use and cost over time were made using ANOVA and Chi Square; p<0.05 for significance. Trends were assessed by linear regression. Results: 895 requests for pamidronate, zoledronic acid, or denosumab were examined over this three year span. The use of bone modifying agents for metastatic cancer is increasing rapidly, as treatment request totaled 171, 269, and 455 for all three agents, pamidronate, zoledronic acid, or denosumab, in 2010, 2011, and 2012, respectively. Zoledronic acid requests significantly increased (p<0.001) per year between 2010 and 2011, as with 2011 and 2012. Denosumab requests are also increasing steadily and sharply in 2012. Conclusions: Each of these three agents has demonstrated clear efficacy in delaying or preventing second skeletal events among patients with metastatic cancer already involving bone. Toxicities among these three agents are comparable in the vast majority of eligible cancer patients. Relative costs should be carefully considered when choosing which agent to use as the use of these agents in general is increasing rapidly and will have a major impact upon overall cancer care costs. [Table: see text]