Amgen Shares Leap on Osteoporosis Trial Results

Shares of Amgen surged Monday after the company reported positive trial results for its osteoporosis drug candidate denosumab—which one analyst terms "a future blockbuster."

After the market closed Friday, Amgen reported late-stage clinical trial results that showed denosumab reduced the incidence of fractured vertebrae in post-menopausal women. Serious side effects were similar to a placebo injection—which, analysts said, will help eliminate concerns about the drug's safety.

The most common side effects were back and joint pain, hypertension and inflamed nasal passages.

Amgen stock climbed more than $7, or 13 percent, to almost $61 after the opening bell.

Rodman & Renshaw analyst Michael King said the results provide clearer data about the benefits and risks of denosumab. Because the side effects were similar to a placebo, he said, the drug's status as "a future blockbuster" is secure.

King raised his rating on Amgen stock to "market outperform" from "market perform," with a price target of $80 per share.

Jefferies analyst Adam Walsh also upgraded the Thousand Oaks, Calif., company to "buy" from "hold" and raised his target to $71 from $47. He estimated peak sales of $2 billion to $3 billion for denosumab—while May-Kin Ho of Goldman Sachs said sales could reach $5 billion if the drug is also approved to treat hormone-induced bone loss in cancer.

Ho said Amgen should report data from a cancer trial in late 2008 or early 2009, and she expects the drug to reach the market in 2010.

She raised her price target to $74 per share from $63.

Amgen is scheduled to release second-quarter results after the bell. Analysts on average expect earnings of $1.02 cents a share, on revenue of $3.58 billion, according to analyst estimates.