UPDATE 1-Amylin loss narrows on lower expenses

* Q1 net loss of 27 cents per share

* Byetta sales slip to $149.8 mln

NEW YORK, April 19 (Reuters) - Amylin Pharmaceuticals Inc (AMLN.O) posted a narrower net loss on Monday helped by lower expenses, despite weaker sales from the Byetta diabetes drug it sells with Eli Lilly and Co (LLY.N).

Amylin posted a net loss of $38.2 million, or 27 cents per share, compared with a net loss of nearly $47 million, or 34 cents per share, a year earlier.

Analysts on average expected a loss of 29 cents per share, according to Thomson Reuters I/B/E/S.

Amylin reported Byetta sales of $149.8 million compared with $157.7 million a year earlier.

Amylin said it was preparing to make available a once-weekly form of Byetta, known as Bydureon, this year andplans to respond this week to concerns by the U.S. Food and Drug Administration.

Last month, the company said the FDA had declined to immediately approve Bydureon but did not ask for lengthy new clinical trials, relieving investors. [ID:nSGE62E0NX] (Reporting by Lewis Krauskopf; Editing by Derek Caney)