UPDATE 1-Amylin shares drop after FDA requests new studies

* Amylin shares drop nearly 10 pct on new study request

* FDA wants more clarity on risks vs benefits of Byetta

(Adds company comment)

BOSTON/NEW YORK, Dec 23 (Reuters) - The shares of Amylin Pharmaceuticals Inc AMLN.O fell nearly 10 percent on Wednesday after the U.S. Food and Drug Administration requested that the company conduct additional safety studies on its diabetes drug, Byetta.

A letter posted on the FDA’s website requested the additional studies to ensure the benefits of Byetta, known generically as exenatide, outweigh the risk of inflammation of the pancreas and acute renal failure.

“We have determined that postmarketing requirements are needed to assess the risk of acute pancreatitis, including fatal and non-fatal hemorrhagic or necrotizing pancreatitis, and the risk of thyroid neoplasms,” the agency said in a letter to the company.

Thyroid neoplasms usually refer to cancer of the thyroid.

“This is all new information to us,” said Yaron Werber, an analyst at Citigroup.

Werber noted the FDA is requiring Amylin to conduct an epidemiological study on acute pancreatitis in Byetta versus non-Byetta patients; epidemiologic queries on pancreatic cancer and thyroid neoplasm in Byetta versus patients taking certain alternative therapies; a clinical trial to see whether Byetta may increase the risk of gall bladder gallstones and therefore pancreatitis.

Epidemiological studies are designed to assess the prevalence of disease in different groups of people.

Amylin said in a statment on Wednesday afternoon that a study has shown “no increased risk of pancreatitis in patients taking Byetta compared to patients taking other antidiabetic medications.”

Amylin also said a pre-clinical program demonstrated “no increased risk of pancreatitis with Byetta” and that it is studying Byetta and gall bladder gallstones.

Byetta, which Amylin makes together with Eli Lilly & Co LLY.N is a member of the GLP-1 class of drugs designed to stimulate the release of insulin in diabetics when glucose levels become too high.

Amylin’s shares fell 9.6 percent to close on Wednesday at $13.97 on Nasdaq. (Reporting by Toni Clarke and Ernest Scheyder; editing by Andre Grenon)