AstraZeneca Plc has been cleared by the U.S. government on account of a major clinical trial that involved the marketing approval for its important new heart drug Brilinta. The Department of Justice (DoJ) has closed the investigation that involved 18,000-patient study and no further action will be taken on the issue.

Last October the Department of Justice had questioned the company as to how it conducted the trial over its medical value of Brilinta. This hampered the sales of the drug. Additionally, the news put the stock under pressure, considering the fact that AstraZeneca viewed Brilinta as a drug with potential sales above $3.5 billion-a-year.

Commenting on the issue, AstraZeneca official Tom Keith-Roach said, “It's frustrating to think of the patients who probably should have been receiving Brilinta for the last nine months but potentially didn't because of this cloud hanging over the brand”.

This was one case where DOJ’s move was highly unusual as traditionally the department has generally focused on potential marketing misconduct by drug makers. This case was the very first time that they were looking into the underlying data behind the granting of a license.

Earlier this year, a takeover bid by Pfizer worth $118 billion was rejected by AstraZeneca and it flagged up the promise of Brilinta in its defense, even though that time the drug was registering modest sales of $216 million.

A study on Brilinta involving 18,000 patients was first reported at a medical meeting in 2009. It was termed PLATO. The study results were presented for successful new drug applications in the United States, Europe and other markets. Eventually, Brilinta was launched in 2011.

Problems started when last year two doctors, James DiNicolantonio of Ithaca, New York and Ales Tomek of Charles University in Prague, raised several questions about the conduct of the study in a paper in the International Journal of Cardiology. This led to the Department of Justice inquiry into the matter.