Amgen (Nasdaq: AMGN) announced that a pivotal, Phase 3, head-to-head trial evaluating denosumab versus Zometa(R) (zoledronic acid) in the treatment of bone metastases in 2,049 patients with advanced breast cancer met its primary and secondary endpoints and demonstrated superior efficacy compared to Zometa. Superiority was demonstrated for both delaying the time to the first on-study Skeletal Related Events (SREs)(fracture, radiation to bone, surgery to bone, or spinal cord compression) (hazard ratio 0.82, 95 percent CI: 0.71, 0.95), and delaying the time to the first-and-subsequent SREs (hazard ratio 0.77, 95 percent CI: 0.66, 0.89). Both results were statistically significant.
Overall, the incidence of adverse events and serious adverse events was consistent with what has previously been reported for these two agents. Of note, osteonecrosis of the jaw (ONJ), which had not been observed in previously reported Phase 3 studies with denosumab, was seen infrequently in both treatment groups. There was no statistically significant difference in the rate of ONJ between the two treatment arms. Infectious adverse events were balanced between the two treatment arms, as was overall survival and the time to cancer progression.
"We are extremely pleased with the outcome of this important study, which shows that denosumab can reduce or delay the serious complications of bone metastases in breast cancer patients better than the current standard of care, and with a favorable benefit/risk profile," said Roger M. Perlmutter, M.D., Ph.D., executive vice president of Research and Development at Amgen. "These results underscore the importance of the RANK Ligand pathway in bone disease, and offer the promise of improved care for patients with advanced breast cancer. We look forward to reviewing the results from a second Phase 3 study of denosumab effects in advanced cancer patients later this year."
Bone metastases, the spread of tumors to the bone, are a serious concern for advanced breast cancer patients, with incidence rates as high as 75 percent. When cancer spreads to the bone, the growing cancer cells weaken and destroy the bone around the tumor. This damage can result in a number of serious bone complications, collectively called SREs.
Full efficacy and safety data will be submitted for presentation at an upcoming medical meeting in the second half of this year.
Study Design
This was an international Phase 3, randomized, double-blind study comparing denosumab with Zometa in the treatment of bone metastases in patients with advanced breast cancer. Patients enrolled in the study were randomized in a one-to-one ratio to receive either 120 mg of denosumab subcutaneously every four weeks (Q4W) or Zometa administered intravenously at a dose of 4 mg single, 15 minute infusion every four weeks as per the labeled use.
In clinical trials testing new medications for bone metastases, treatment success has been measured by whether the bone complications, or SREs, caused by the tumor are reduced or delayed. The primary and secondary endpoints of the denosumab bone metastases studies use a composite endpoint of four SREs - fracture, radiation to bone, surgery to bone, and spinal cord compression - to measure the effectiveness of denosumab versus Zometa.
The primary endpoint was to evaluate if denosumab is non-inferior to Zometa with respect to the first on-study SRE in patients with advanced breast cancer and bone metastases. Secondary endpoints were to evaluate if denosumab was superior to Zometa with respect to the first on-study SRE, as well as first-and-subsequent on-study SREs, and to assess the safety and tolerability of denosumab compared with Zometa.
About Denosumab and Amgen's Research in Bone Biology
Denosumab is the first fully human monoclonal antibody in late stage clinical development that specifically targets RANK Ligand, the essential regulator of osteoclasts (the cells that break down bone). With more than 19,000 patients in trials across indications worldwide, the denosumab development program is the largest ever initiated by Amgen. This broad and deep development program demonstrates Amgen's commitment to researching and delivering pioneering medicines to patients with unmet medical needs. Amgen is studying denosumab in numerous tumor types across the spectrum of cancer induced bone disease. Over 11,000 patients have been enrolled in the denosumab oncology clinical trials testing the drug for bone loss and destruction associated with cancer treatment-induced bone loss in breast and prostate cancers, for the prevention of skeletal related events due to the spread of cancer to the bone in multiple myeloma and multiple solid tumors, and for its potential to delay bone metastases in prostate cancer.
Bone Metastases: Impact and Prevalence
Bone metastases, cancer cells that separate from tumors and migrate to bone tissue where they settle and grow, occur in more than 1.5 million people worldwide.(1) With improvements in cancer care, including earlier diagnosis and new treatment options, leading to increases in survival rates(2), the number of patients developing metastatic disease secondary to a primary cancer is increasing. Bone metastases are a significant problem for patients with certain types of advanced cancer, with incidence rates of nearly 100 percent in myeloma patients and as high as 75 percent in breast and prostate cancer patients.
With bone metastases the growing cancer cells weaken and destroy the bone around the tumor. The damage the tumor has caused to the bone can result in a number of serious complications, collectively called skeletal related events (SREs). These include fracture of a bone, radiation to bone, surgery to bone, or spinal cord compression. All are serious complications for advanced cancer patients.
The economic burden of U.S. patients with bone metastases is significant and was estimated to be $12.6 billion last year.(3) Patients with bone metastases who experience an SRE incur significantly higher medical costs compared with those who do not experience an SRE.(4)
About Amgen
Amgen discovers, develops and delivers innovative human therapeutics. A biotechnology pioneer since 1980, Amgen was one of the first companies to realize the new science's promise by bringing safe and effective medicines from lab, to manufacturing plant, to patient. Amgen therapeutics have changed the practice of medicine, helping millions of people around the world in the fight against cancer, kidney disease, rheumatoid arthritis, and other serious illnesses. With a deep and broad pipeline of potential new medicines, Amgen remains committed to advancing science to dramatically improve people's lives. To learn more about our pioneering science and our vital medicines, visit www.amgen.com.
(1) Capanna R, Coia LR, Coleman R. et al. eds. Textbook of Bone Metastases. Hoboken, NJ: Edition: John Wiley and Sons; 2005:105.
(2) Mundy GR. Metastasis to bone: causes, consequences and therapeutic opportunities. Nat Rev Cancer. 2002 Aug;2(8):584-93.
(3) Schulman K and Kohles J. Cancer. 2007;109:2334-2342
(4) GVD/Barber ISPOR 2008 Poster; Schulman 2007; Delea et al. 2006