Drugmaker Eli Lilly says federal health regulators have delayed a decision on its experimental blood thinner prasugrel, a drug some analysts see as a potential blockbuster.

Lilly faces a wave of patient expirations in the next few years. That includes the patent protecting its top-selling drug, the anti-psychotic Zyprexa. That drug brought in more than $4 billion in sales last year.

The FDA has been reviewing the drug since January, but scientists delayed a decision in June, saying they needed more time.

Indianapolis-based Lilly developed the drug with Japanese drugmaker Daiichi Sankyo Co. It is designed to treat patients with heart problems who are at risk of developing blood clots.