It's a good news-good news day for Amgen ($AMGN). The company's new bone drug is gathering indications--and potential sales--like a snowball rolling downhill. Under the name Prolia, the drug won FDA approval for bone loss in breast cancer patients using aromatase inhibitors. And it got the FDA nod for prostate cancer patients undergoing androgen-deprivation therapy.
In both groups, the cancer treatments reduce hormone levels, which can lead to bone loss and can increase the risk of fractures. The approvals are based on two trials--one in 1,468 men on androgen-deprivation therapy and another in 252 post-menopausal women using aromatase inhibitors. The incidence of vertebral fractures after three years of treatment was 1.5% in men on Prolia, compared with 3.9% in men on placebo. In women, the difference in bone mineral density in the lumbar spine after two years of treatment was 7.6%, the company said.
Meanwhile, Prolia scored in long-term results from an extended trial. Post-menopausal women treated with Prolia for up to 8 years saw their bone mineral density increase by 16.8% on average in the lumbar spine and 6.9% in the hip, and no new safety concerns arose. The Freedom study had flagged 12 skin infections in patients using Prolia, and in the extension study, two more cases of serious cellulitis occurred. The extension study included more than 4,500 women.
"I think that's informative as to what the long-term trend might be," researcher Dr. Henry Bone said at the annual meeting of the American Society for Bone and Mineral Research (as quoted by MedPage Today). Prolia is already approved to treat post-menopausal osteoporosis in women at increased risk of fracture. Amgen is studying the drug for other uses as well.
The company is relying on Prolia--which is also sold under the brand name Xgeva to prevent fractures in cancer patients whose tumors have spread to the bone--to help offset slowing sales of its anemia drugs Aranesp and Epogen. Analysts expect the drug to surpass $1 billion in sales by 2014, despite slow-out-of-the-gate sales for the first couple of quarters after its June 2010 launch, MarketWatch reports.