Results from a new study showed patients with type-2 diabetes mellitus who also had coronary artery disease (CAD) and received a 60 mg loading dose and 10 mg maintenance dose of Effient (prasugrel) achieved significantly greater platelet inhibition compared with a 600 mg loading dose and 150 mg maintenance dose of Plavix (clopidogrel). These data were presented at the American Heart Association 2009 Scientific Sessions.

The Optimus-3 study, which evaluated 35 patients with type-2 diabetes who also had CAD and were taking aspirin, showed that within four hours, the level of platelet inhibition as measured using the VerifyNow P2Y12 Test with a 60 mg loading dose of Effient was higher than observed with a 600 mg loading dose of clopidogrel (89 per cent vs. 28 per cent inhibition of platelet activation [IPA], respectively; P<0.0001). In addition, one hour after the loading dose, patients who received Effient had 50 percent IPA compared with 13 per cent in patients who received clopidogrel. The level of platelet inhibition achieved for each drug at four hours was unchanged over the following 24 hours. A 600 mg loading dose of clopidogrel is not currently approved for use.

"Previous research has shown that patients with type 2 diabetes mellitus have more active platelets, so might be more prone to clotting, than non-diabetics, and may have suboptimal response to therapies that reduce platelet activity," said Dominick Angiolillo, assistant professor of Medicine and director of Cardiovascular Research, Division of Cardiology, University of Florida, Jacksonville, Florida. "This study was designed to compare the antiplatelet activity of prasugrel (Effient) used at standard doses with high doses of clopidogrel (Plavix) in patients with type-2 diabetes mellitus who also had coronary artery disease."

The study also looked at the maintenance doses of Effient and clopidogrel. After seven days, results showed that a 10 mg maintenance dose of Effient achieved greater platelet inhibition than a 150 mg maintenance dose of clopidogrel (62 per cent vs. 44 per cent IPA, respectively; P<0.0001).

This study was performed in patients who did not have a specific indication for clopidogrel therapy (more than 12 months after an acute coronary event or bare metal stent placement and no drug eluting stent in place). The relationship between inhibition of platelet aggregation and clinical activity has not been established.

Optimus-3 (Third Optimizing anti-Platelet Therapy In Diabetes MellitUS) evaluated the pharmacodynamic effects of Effient compared with clopidogrel in 35 patients with type-2 diabetes mellitus who also had CAD and were taking aspirin.

Daiichi Sankyo Company, Limited, and Eli Lilly and Company co-developed Effient, an oral antiplatelet agent discovered by Daiichi Sankyo and its Japanese research partner, Ube Industries, Ltd. Effient helps keep blood platelets from clumping together and developing a blockage in an artery.