CORRECTED - Prasugrel better for diabetes patients than Plavix

(Corrects heart-attack frequency figures in paragraph 5)

MUNICH, Aug 31 (Reuters) - Eli Lilly (LLY.N) and Daiichi Sankyo's (4568.T) new blood-thinning drug prasugrel appears better for diabetes patients than Plavix, researchers said on Sunday.

Prasugrel -- a rival to Plavix from Sanofi-Aventis (SASY.PA) and Bristol-Myers Squibb (BMY.N) -- is a key product for Lilly and Daiichi. But its path to market has been delayed and the drug has been associated with serious bleeding.

That has left doctors debating how it might best be used, assuming it is approved by regulators.

Stephen Wiviott of the Brigham and Women's Hospital in Boston said a new analysis of results from the previously reported TRITON-TIMI 38 clinical trial showed the benefit of prasugrel tended to be greater in patients with diabetes than those without the condition.

Patients were 40 percent less likely to suffer a subsequent heart attack if they got prasugrel, with this occurring in 8.2 percent of people against 13.2 percent of those on Plavix, he told the annual meeting of the European Society of Cardiology.

In non-diabetics, there was a much smaller difference.

The findings suggest that a more powerful drug may be more effective in the growing group of diabetic patients who are at high risk of suffering a second heart attack.

The U.S. Food and Drug Administration is due to give its verdict on prasugrel by Sept. 26.

Industry analysts believe the agency's decision to delay a decision on whether to approve the product could be due in part to uncertainty over how to define precisely which patients should use it.

Plavix is one of the world's biggest ever drugs, with worldwide sales in 2007 of more than $8 billion and prasugrel is also seen as a potential blockbuster, as long as concerns about bleeding do not derail the medicine.

Both treatments work by stopping blood cells called platelets from clumping together. (Reporting by Ben Hirschler)