UPDATE 3-US FDA wants input on Amgen bone drug risks
* Panel asked to weigh serious infections, cancers
* Analysts expect panel to back denosumab
* Advisory panel to review drug Thursday
* Amgen shares gain 2.56 percent (Updates share price)
WASHINGTON, Aug 11 (Reuters) - Serious infections and cancers must be considered as U.S. advisers weigh the future of Amgen Inc's (AMGN.O) most important experimental medicine, drug reviewers said in documents released on Tuesday.
Shares of the world's largest biotechnology company rose 2.56 percent to close at $62.81 on Nasdaq. Analysts said the safety issues were known to investors and they expected an advisory panel to recommend approval of the drug, denosumab.
Amgen is seeking U.S. Food and Drug Administration approval to sell the injection under the name Prolia in an $8 billion market for osteoporosis drugs.
The company's studies raised questions about the risk of serious infections, new cancer cases and other problems seen in denosumab patients, FDA reviewers said in a memo prepared for an advisory panel review on Thursday.
"Of particular concern, in light of these safety issues, is whether the risk/benefit balance for the osteoporosis prevention indication, both for patients with and without cancer, supports approval," FDA staff said.
BMO Markets analyst Jason Zhang said the safety issues were "not surprising" and he felt the panel likely would vote in favor of the drug. Zhang expects denosumab to garner annual sales of $2.4 billion by 2012.
"People always worry about cancer and malignancies, but when you look at the incidence (with denosumab), you can't really have statistical analysis because they are so rare," he said.
Zhang also said investors may be comforted by the fact that FDA reviewers did not recommend a strict risk management program for the drug.
Cowen & Co analyst Eric Schmidt said the FDA documents "read fairly cautiously" and "it doesn't seem like the FDA has yet made up its mind about the risk/benefit of the drug."
He said he expected the panel would recommend approval, echoing the general consensus of other analysts. A pressing uncertainty is whether the panel will recommend a risk management program (REMS) or other potential warnings.
"If a stringent REMS program were required here, the stock could be down $3 or $4 on that," Schmidt said. Continued...
