The newspaper said the findings, which it said it obtained, reported that if all diabetics now taking Avandia were given Takeda's Actos drug instead, about 500 heart attacks and 300 cases of heart failure would be averted each month because Avandia, also known as rosiglitazone, can be harmful to the heart.
"Rosiglitazone should be removed from the market," one report, by Dr. David Graham and Dr. Kate Gelperin of the FDA concluded, according to the Times, which said both authors recommended Avandia's withdrawal from the market.
Sales of Avandia, once Glaxo's second biggest-selling product, plummeted two years ago after a U.S. study linked it to an increased risk of heart attack in a conclusion disputed by Glaxo.
The Times said an FDA advisory board voted, 8-7, in 2007 to accept the advice of an independent committee that while Avandia might increase the risk of heart attack, it should stay on the market.
A Canadian study last year found that Avandia was associated with an increased risk of heart failure and death among older patients compared with Actos.
Glaxo contested the findings, which it said did not reflect evidence from two randomized controlled trials comparing Avandia and Actos that found no differences in heart failure.
The drugmaker is enrolling patients into a long-term clinical trial that will look at cardiovascular outcomes and compare the effect of the two drugs.
The Times said the internal FDA findings reflected a fierce debate inside the agency about Avandia. The newspaper quoted Glaxo as saying it had studied Avandia extensively and that "scientific evidence simply does not establish that Avandia increases" heart attack risk.
Dr. Janet Woodcock, director of the FDA's drug center, wrote in a December 2009 internal memorandum that "there are multiple conflicting opinions" about Avandia and ordered officials to assemble another advisory committee to reconsider if the drug should be sold, according to the Times.
It quoted FDA Commissioner Margaret Hamburg as saying on Friday, "I await the recommendations of the advisory committee."
A bipartisan U.S. Senate investigation said Glaxo failed to warn patients earlier that Avandia was potentially deadly, according to the Times. The newspaper reported that the results, which it said it also obtained, were expected to be released on Monday.
The Times quoted GlaxoSmithKline as saying it disagreed with the Senate investigation's conclusions. It added that the company declined comment on internal FDA. documents but that "the official ruling from FDA is that Avandia remain on the market."