NEW YORK (Reuters) - Amylin Pharmaceuticals' shares lost half their value in premarket trading on Wednesday, after U.S. regulators declined to approve its long-acting diabetes drug until more data is obtained on its potential effect on heart rates.
Shares of drug-development partners Eli Lilly and Co
Amylin was trading at $10.01, from its Tuesday close of $20.49 on the Nasdaq.
The companies said they would reply to the Food and Drug Administration by the end of next year -- meaning the agency is unlikely to make a decision until mid-2012.
Lilly shares were down 6 percent at $35.25, from Tuesday's close of $37.45 on the New York Stock Exchange. The Indianapolis drugmaker, which badly needs new drugs to offset looming generic competition for its flagship schizophrenia drug, has been counting heavily on Bydureon to be approved and become a blockbuster in its own right.
Analysts have projected annual sales of more than $1 billion for Bydureon, a once-weekly version of Lilly's widely used Byetta treatment for Type II diabetes.
Bydureon uses technology from Alkermes Inc, whose own shares fell 26 percent to $10.69 in premarket trading, from a closing price of $14.50 Tuesday on the Nasdaq.
(Reporting by Ransdell Pierson, editing by Maureen Bavdek)