U.S. regulatory advisers will reconsider restrictions on the use of GlaxoSmithKline’s Avandia after a second look at the once best-selling diabetes pill found it doesn’t increase overall cardiac death risk.

Previous findings by Glaxo (NYSE: GSK) that Avandia doesn’t raise the overall risk of death, heart attack or stroke are supported by a reanalysis of the data by independent researchers at Duke University, Food and Drug Administration staff said in a report today.

FDA advisers are set to meet June 5-6 about the findings, an unusual gathering to consider a reanalysis of data more than two years after the agency imposed strict limits on prescribing Avandia and the company agreed to stop promoting the drug. However, no decisions have been made about Avandia, the FDA noted. 

“It is important to note that FDA has not reached any final updated conclusions” on the cardiovascular safety of Avandia based on the reassessment, said Mary Parks, director of the FDA’s division of metabolism and endocrinology products.

The former blockbuster-selling drug was subjected to major safety restrictions in 2010.

The meeting is highly unusual.

The positive safety review from Duke researchers is the latest twist in a years-long debate over Avandia, which has divided medical experts, cost Glaxo billions of dollars and possibly resulted in an unknown number of patient heart attacks.

First approved in 1999, Avandia became the top-selling diabetes pill in the world by 2006 with sales of $3.4 billion. But prescriptions plummeted the following year after an analysis of dozens of studies suggested Avandia could raise the risk of heart attack.

For three years the FDA struggled to answer a seemingly simple question: Does Avandia increase the risk of heart attacks? A definitive answer has never been reached, in part because patients with diabetes are already predisposed to heart attacks. That makes it extremely difficult to tell which heart problems are drug-related and which are simply a result of the underlying disease.

Finally in 2010 the FDA decided to restrict the drug’s use to all but the rarest of cases. Regulators in Europe banned the drug outright.

The FDA’s safety restrictions will get a second look this Wednesday and Thursday at a meeting prompted by a new analysis of the lone study designed to assess Avandia’s heart risks. Known as RECORD, the study followed 4,400 patients and tracked rates of heart attack, hospitalization and death for six years.

The results were first reported in 2009 and medical experts have been debating their legitimacy ever since.

At the last Avandia panel meeting in 2010, FDA leadership generally backed RECORD’s findings that Avandia appeared as safe as other standard diabetes drugs. But FDA staff scientists said the study was unreliable because of underreported heart attacks and other design flaws. Because of that disagreement the FDA asked Glaxo to obtain an independent analysis by an outside party.

The new analysis by the Duke Clinical Research Institute generally supports Glaxo’s original findings. In documents posted Monday, an FDA review of Duke’s analysis states: “These results show no statistically significant evidence to suggest an increased cardiovascular risk.”

Despite that assessment, the FDA documents state that the agency “has not reached any final updated conclusions” on the heart safety of Avandia.

The FDA will seek advice from two panels comprised of outside experts in diabetes and drug safety. The panelists will be asked to vote on four options for Avandia:

  • Removing the drug’s safety restrictions
  • Leaving the safety restrictions in place
  • Modifying the safety restrictions
  • Withdrawing the drug from the market entirely

At the last FDA meeting on Avandia in 2010, the panelists voted 21 to 12 to leave Avandia on the market. The group’s recommendations are not binding and are only one part of the government’s decision-making process.

GSK operates its North American headquarters in RTP.

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