Amgen may revise drug label; shares sink

Shares of Amgen Inc. fell the most in seven months Friday after the biotech company said it might revise the safety information on its biggest product, anemia drug Aranesp.

Amgen fell $3.05, or 5.5%, to $52.10, the most since May 10, when a Food and Drug Administration panel suggested new restrictions in prescribing information for the anemia drug.

An FDA advisory panel will meet before the end of March “as part of the ongoing review” of the class of drugs including Aranesp that stimulate the bone marrow to make more red blood cells, Amgen said Thursday.

A preliminary study showed that more breast-cancer patients who took Aranesp, which counters weakness and fatigue from chemotherapy, died or had growing tumors than those who did not receive the drug, Amgen said last week.

“We anticipate another difficult meeting for Amgen, possibly resulting in the exclusion of breast cancer from the Aranesp label,” said analyst Christopher Raymond at Robert W. Baird & Co. in Chicago.

If the condition is excluded, the company could potentially lose $260 million in 2009 sales, he said.

Thousand Oaks-based Amgen has lost about $19 billion in market value this year after studies showed its anemia drugs raised the risk of heart attack, stroke and death at high doses.

Aranesp generated $4.12 billion in sales last year.

The labeling change will take into account the breast cancer study results and recently published follow-up research on patients with cervical cancer, Amgen said.