Updated from 10:42 a.m. ESTShares of Amylin Pharmaceuticals ( AMLN) plummeted Tuesday after its partner Alkermes ( ALKS) disclosed in a filing with the Securities and Exchange Commission the likelihood of regulatory delays for Byetta LAR. Shares of Amylin were giving up 20% to $8.49 in recent trading Tuesday, while Alkermes was shedding 9.8% to $9.11. Alkermes said it recently received feedback from the Food and Drug Administration that data submitted as part of its new-drug application (NDA) for a long-acting version of diabetes drug Byetta do not meet FDA requirements. The data are from "correlation studies" that Amylin submitted to show that the drug manufactured by Alkermes in its facility and used in clinical trials was the same as that manufactured on a commercial scale in Amylin's facilty. According to the filing, Amylin is in active discussions with the U.S. regulatory agency regarding the options to allow the application to be filed by the end of the first half of 2009.