Federal regulators delay Eli Lilly blood thinner

The drug, called prasugrel, is considered crucial to Indianapolis-based Lilly, which faces a wave of patent expirations in the next few years.

Lilly said in a statement the Food and Drug Administration has still not completed its review of the drug, which was submitted in January. Agency scientists already delayed a decision on June, saying they needed more time.

"This is a very large, complex submission, and it should not be surprising that delays occur," Jennifer Stotka, a vice president with Lilly, said in a statement. The company said it would not speculate on the cause of the delay.

Lilly developed the drug with Japanese drugmaker Daiichi Sankyo Co. Prasugrel is designed to treat patients with acute heart problems such as heart attacks or unstable angina who are at risk of developing blood clots.

The drug's approval is key for Lilly's financial outlook, as the patent on its best-selling drug, the anti-psychotic Zyprexa, is due to expire in 2011. Zyprexa contributed more than a quarter of the company's $18.6 billion in sales last year.

Analysts said prasugrel could bring in anywhere from $600 million to $1 billion in revenue.

UBS analyst Roopesh Patel said it was hard to draw conclusions from Lilly's statement because it simply said the FDA had not completed its review.

"Based on this, one can't necessarily conclude as to whether or not the final outcome would be positive or negative," Patel said.

He thinks Lilly will have to wait weeks or maybe months to hear more from the FDA.