AstraZeneca PLC said its prescription blood-thinning medicine Brilinta failed to show a benefit over standard treatment in peripheral artery disease in a large clinical trial, denting the company's growth ambitions for one of its most important drugs.

The U.K.-based drugmaker said Tuesday that Brilinta was no better than generic blood-thinner clopidogrel at reducing heart problems in people with peripheral artery disease, a condition in which a buildup of fatty deposits in the arteries restricts blood flow to the leg muscles.

The failure cuts off a source of significant growth for Brilinta: peripheral artery disease affects around 8.5 million people in the U.S. according to the Centers for Disease Control and Prevention. Success could have boosted the drugs' sales by around $2 billion at peak, according to an estimate by UBS.

The result will put pressure on the company's ambition to increase sales of Brilinta to $3.5 billion by 2023, an important part of its overall target to nearly double revenue to $45 billion in the same period. AstraZeneca unveiled those goals to fend off an unwanted takeover approach from U.S. rival Pfizer Inc. nearly two years ago. Brilinta sales were $619 million in 2015.

The drugmaker is plowing significant investment into a huge clinical trial program for Brilinta, aimed at expanding its use. The drug is already marketed as a treatment for people who have suffered a heart attack, to lower their risk of having a second one.

Those efforts have met with mixed results. Earlier this year, another large trial failed to show that Brilinta was any better than aspirin at preventing stroke.

Sean Bohen, Executive Vice President, Global Medicines Development and Chief Medical Officer at AstraZeneca, said he was disappointed with the results but said they didn't effect the "proven benefits of Brilinta in acute coronary syndrome and post-myocardial infarction patients," referring to those who have suffered a heart attack.

Shares in AstraZeneca were down 1.0% at £ 49.93 on Tuesday morning.

Write to Denise Roland at Denise.Roland@wsj.com

(END) Dow Jones Newswires

October 04, 2016 05:05 ET (09:05 GMT)

Copyright (c) 2016 Dow Jones & Company, Inc.
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