UPDATE 4-Lilly, Daiichi blood-thinning drug faces FDA delay

(Adds Lilly comment, further analyst comment; updates shares)

By Sachi Izumi and Ben Hirschler

TOKYO/LONDON, June 24 (Reuters) - U.S. regulators have extended the review period for Eli Lilly and Co (LLY.N) and Daiichi Sankyo's (4568.T) new blood-thinning drug prasugrel, delaying a decision on approval by three months.

Lilly shares fell as much as 3.4 percent in New York trading on Tuesday to their lowest in about six years. Daiichi shares slumped 2.3 percent in Tokyo.

Prasugrel -- a rival to Plavix from Sanofi-Aventis (SASY.PA) and Bristol-Myers Squibb Co (BMY.N) -- is a critical experimental medicine for Lilly and Daiichi.

The companies said the Food and Drug Administration's review period would now run until Sept. 26 to complete a review of supplemental information about the drug.

Devesh Singh, an analyst with Mehta Partners, predicted that prasugrel would win approval by the new deadline, noting the delay did not reflect concerns about the medicine.

"We don't see anything changing our view on prasugrel ... because this delay is not related to the drug," Singh said, adding that he believed Daiichi and Lilly shares would soon recover Tuesday's losses.

Lilly and Daiichi submitted their application to the FDA on Dec. 26 for prasugrel. The application was reviewed on a priority basis, which shortens the review time to six months from the typical 10 to 12 months.