Amgen says key bone drug trial meets goals

By Deena Beasley

LOS ANGELES (Reuters) - Amgen Inc (AMGN.O: Quote, Profile, Research, Stock Buzz) said its experimental osteoporosis drug, denosumab, significantly reduced the risk of bone fracture in post-menopausal women in a large trial.

The news triggered a 15 percent rise in Amgen's shares even though key data won't be unveiled until September.

Denosumab, a bioengineered antibody that targets a protein involved with bone-destroying cells called osteoclasts, is seen as critical to Amgen's future now that growth of its flagship anemia drug franchise, which includes Epogen and Aranesp, has waned due to safety concerns.

The positive trial result "almost guarantees denosumab a place in the osteoporosis market ...," Morgan Stanley analyst Steven Harr said in a research note.

He estimated peak annual sales at $2 billion to $3 billion.

Amgen said the 7,800 patient, three-year trial found that a twice-yearly injection of denosumab led to a statistically significant reduction in the incidence of new spinal fractures, compared with a placebo injection.

The study also showed that denosumab significantly reduced the risk of new non-spinal and hip fractures and side effects were similar for both patient groups, the company said.

"We are encouraged by the magnitude and consistency of the treatment effect and pleased with the safety results," said Roger Perlmutter, Amgen's head of research and development.