Amgen ( AMGN - Get Report) appears to have another blockbuster drug in its bag, and shares of the biotech company rose accordingly Tuesday.

Denosumab, a new drug designed to inhibit bone loss, reduced the risk of new spine and hip fractures by 68% and 40%, respectively, compared to placebo, according to results from a highly anticipated clinical study of post-menopausal women with osteoporosis that were presented Tuesday morning at a meeting of bone specialists.

The results were generally in line with investor expectations. Amgen shares were up $1.57, or 2.52%, to $63.76 in recent trading.

Amgen is counting on denosumab to help lift the company from a recent malaise caused by falling sales of its anemia drugs, which had been linked to deaths, cardiovascular problems and cancer growth.

Amgen first announced that the so-called FREEDOM study of denosumab was a success in late July, but it withheld details until it could present them Tuesday morning at the American Society for Bone and Mineral Research annual meeting.

Amgen shares have risen about 15% since late July on the belief that denosumab, given as a twice-yearly injection to treat osteoporosis, will generate $2 billion to $3 billion in new revenue for Amgen, according to various analyst estimates.

Denosumab's ultimate commercial potential, however, will depend on how the drug's efficacy and safety compare to currently marketed osteoporosis treatments, including cheap, generic versions of Merck's ( MRK - Get Report) Fosamax pill and a once-yearly intravenous drug from Novartis ( NVS - Get Report), known as Reclast.

Osteoporosis is a disease characterized by weak and brittle bones, so the most important clinical measure for any osteoporosis drug is its ability to reduce the number and frequency of bone fractures, typically measured at the spine, and more important, the hip.

In prior studies, Fosamax reduced the relative risk of vertebral and hip fractures by 47% and 51%, respectively. For Reclast, the vertebral and hip fracture reduction rates from previous studies were 70% and 41%, respectively.

None of these bone-fracture studies tested denosumab against Fosamax or Reclast directly, but that doesn't stop doctors and investors from comparing results.

On these efficacy measures, denosumab appears to be comparable to Reclast, although the denosumab patients entering the FREEDOM study had fewer previous fractures, which makes it more difficult for denosumab to lower the risk of fracture rates.

Generally speaking, most analysts and investors were expecting denosumab to reduce hip fractures in the range of 40% to 50% -- in line with its competitors.

On the safety side of FREEDOM's ledger, the rate of serious infections was comparable between denosumab and placebo at 53% vs. 54%.

Denosumab is a monoclonal antibody discovered by Amgen scientists that works against osteoporosis in an entirely new way by blocking a protein called RANK Ligand involved with the breakdown of bone.

In recent trading, Amgen was up $2.49, or 4%, at $64.68.

Adam Feuerstein writes regularly for TheStreet.com. In keeping with TSC's editorial policy, he doesn't own or short individual stocks, although he owns stock in TheStreet.com. He also doesn't invest in hedge funds or other private investment partnerships. Feuerstein appreciates your feedback; click here to send him an email.