Trasylol patients were 27 percent more likely to die than those getting a rival drug a decade after open-heart surgery, according to a review of 10,275 patients at Duke University Medical Center. Another study of 78,199 patients, presented to regulators last year after Bayer initially withheld the data, found a 78 percent higher death risk a week after surgery. Both were published in The New England Journal of Medicine.

The controversial med was approved in the US in 1993 to reduce transfusions and bleeding during open-heart surgery, but a 2006 study linked the drug to higher rates of heart attack, stroke, kidney failure and death. Those findings prompted the FDA to hold a meeting to review Trasylol, but Bayer failed to provide data showing a higher risk of death and stroke, even though its own scientists attended the meeting. The internal data was disclosed several days after the meeting, leading to charges of a cover-up, which Bayer last summer denied.

In November, however, Bayer suspended sales after a pivotal Canadian trial linked the drug to higher death rates. “It’s become part of the fabric of cardiac surgery for the past decade,” Andrew Shaw, lead author of one study and associate professor of anesthesiology at Duke, tells Bloomberg News. “Our study doesn’t provide a definitive answer, but it intensifies the debate over the drug safety.”

Indeed, the lives of 22,000 people could have been saved if the FDA removed Bayer’s Trasylol two years ago, when the study revealed a growing number of deaths linked to the heart drug, according to the researcher who conducted the study.

Bayer, meanwhile, challenged the findings from the latest studies, raising questions about how the researchers analyzed the data and accounted for differences between the patients getting Trasylol and an alternative known as aminocaproic acid. The drugmaker continues to wait for a detailed analysis of the Canadian trial.

“At that time, the temporary marketing suspension will be re-evaluated,” Bayer spokeswoman Staci Gouveia tells Bloomberg, adding that Bayer has no idea when the details will be available. “Bayer believes that the totality of the available data continue to support a favorable risk-benefit profile for Trasylol.”

More than 200,000 bypass patients a year worldwide were getting Trasylol before sales were halted, Bloomberg notes, adding that Bayer has said 4.3 million people have been treated with Trayslol and that the injectable drug costs 10 times more than its closest rival.

“It is the largest cohort study ever on the issue, representing routine care. It’s another data point in the accumulating number of studies that show this increased risk of death,” Sebastian Schneeweiss, the lead researcher of the second study and an associate professor of medicine at Harvard Medical School in Bostonrhe tells Bloomberg, while declining to say if he thought Trasylol should be permanently removed from the market.

“The data have to be reviewed and seen in the light of all the evidence. The bottom line is there are still more people dying using this drug. FDA is the agency that has all the evidence together at this point, and they need to make an informed decision.”

Currently, doctors can get it through a restricted access program in the US.

In an editorial, Wayne Ray, director of drug epidemiology and professor of preventive medicine at Vanderbilt University School of Medicine, wrote: “The manufacturer cannot be relied on to perform these studies voluntarily, because they frequently serve no commercial purpose.” As a result, studies “supervised by the FDA, should be mandatory. To limit the risk for patients, distribution of new drugs should be restricted while these trials are being conducted, with selective extension of patents to reduce the economic burden on manufacturers.”