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.

Dr. Anthony Ware, a Lilly vice president who leads cardiovascular and acute care development, said the companies remained confident in the overall submission package.

The FDA had asked for additional analyses of the data, Ware said, although he declined to specify the information that the agency requested.

"There's been nothing that's stumped us," Ware said in an interview.

The prasugrel application is the largest in Lilly's history, Ware said. "They certainly have a lot to review in a short period of time," he said.

Meanwhile, Sanofi shares rose 1.4 percent in Paris, while Bristol-Myers shares were down less than 1 percent.

"This news will come as a welcome but likely temporary respite to Sanofi-Aventis and Bristol-Myers," said Nomura Code analyst Mike Ward.

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