GlaxoSmithKline’s (NYSE: GSK) much-maligned diabetes drug Avandia will be released from restrictions preventing sales to certain patients after U.S. regulators determined new data show the medicine doesn’t raise heart risks.

The Food and Drug Administration reviewed independent researchers’ reanalysis of a Glaxo study, called Record, that confirmed Avandia doesn’t raise the risk of death, heart attack or stroke. Avandia’s reign atop the diabetes market as a $3 billion-a-year medicine began to end after a 2007 New England Journal of Medicine article found a 43 percent increased risk of heart attack in patients taking the drug in a combination of results from smaller studies.

“Given these new results, our level of concern is considerably reduced; thus, we are requiring the removal of certain prescribing restrictions,” Janet Woodcock, director of the FDA’s Center for Drug Evaluation and Research, said yesterday in a statement.

Since researchers needed to know who was on Avandia, the Record study wasn’t blinded, a method that prevents participants in a clinical trial from knowing who is on the drug. The data were reanalyzed by Duke University School of Medicine in Durham. Thomas Marciniak, the medical team leader in the FDA’s Division of Cardiovascular and Renal Products, questioned in June whether Record’s trial design biased the data, rendering Duke’s assessment moot.

“GSK welcomes the decision of the FDA and appreciates the Agency’s robust review of the science with regard to Avandia,” the company said in a statement.

“GSK maintains its view that Avandia is a safe and effective treatment for Type 2 diabetes when used appropriately.The company will work with the FDA to update labeling and to implement the Agency’s decisions regarding easing restrictions on the medicine.”

GSK operates its North American headquarters in RTP.

Panel Recommendation

FDA advisers met in June to discuss the reanalysis of Record and voted that restrictions on the drug should be lifted.

The agency also released London-based Glaxo from a requirement to conduct a trial comparing Avandia to Takeda Pharmaceutical Co.’s Actos.

Avandia was approved in 1999 and sales had dropped to $9.5 million last year. The patent on the drug expired in 2011.

The FDA restricted Avandia in 2010 in the U.S. to patients who couldn’t control their diabetes on other medications and mandated doctors and pharmacies that prescribe and dispense the drug be certified. Patients, pharmacies and doctors will no longer be required to enroll in a program that monitors Avandia use, rather Glaxo will be responsible for ensuring prescribers are given training on cardiovascular risk, the FDA said.

Glaxo paid a record $3 billion fine last year in the U.S. for illegally marketing medicines. As part of the settlement, the drugmaker pleaded guilty to failing to report safety data on Avandia. European regulators ordered the treatment pulled from their market in 2010.