The drugmaker has agreed to suspend marketing of its troubled med, which is used to control bleeding during heart surgery, pending a detailed review of preliminary results from a Canadian study that suggested an increased risk for death. Two weeks ago, the FDA announced plans for a review after the Data Safety Monitoring Board for the trial of 3,000 Canadian surgery patients recommended halting the study after early findings pointed to a greater chance of dying compared with two other drugs.

In explaining its decision, the FDA cited the “serious nature of the outcomes suggested in the preliminary data.” The agency says it hasn’t yet received full study data but expects to act quickly with Bayer, the study’s researchers at the Ottawa Health Research Institute, and other regulatory agencies to undertake a thorough analysis of data to better understand the risks and benefits of Trasylol. You can read Bayer’s statement here.

Trasylol has a tortured history. A year ago, an FDA panel met to review data showing Trasylol was linked to a higher risk of death, kidney failure, congestive heart failure and stroke. The panel declared Trasylol was safe and effective, and voted unanimously to keep the med on the market. But a few days later, the FDA was contacted by a Bayer consultant at Harvard’s School of Public Health, who said Bayer hid evidence. He was hired by Bayer six months earlier to review a 67,000-patient database and compare Trasylol side effects with two other anti-bleeding drugs. A warning was placed on the product label and usage was limited to patients at an increased risk for blood loss and blood transfusion during coronary bypass graft surgery

But the disclosure caused a furor, especially after it became known that Bayer employees failed to notify the FDA of the study, which showed that Trasylol can increase risk of death, kidney damage, heart failure and stroke. To clear its name, Bayer hired an outside lawyer to investigate. And this summer, prior to the latest FDA panel meeting, the drugmaker insisted the cover-up was no cover-up, but merely a misunderstanding by two employees.

The FDA goes on to say this morning that there aren’t many treatment options for patients at risk for excessive bleeding during cardiac surgery. So the agency is working with Bayer to “phase Trasylol out of the marketplace in a way that does not cause shortages of other drugs used for this purpose.”

“Until FDA can review the data from the terminated study it is not possible to determine and identify a population of patients undergoing cardiac surgery for which the benefits of Trasylol outweigh the risks. Understanding that individual doctors may identify specific cases where benefit outweighs risk, FDA is committed to exploring ways for those doctors to have continued, limited access to Trasylol,” the agency says.

The other drugs in the Canadian study, known as Bart, were also antifibrinolytic drugs, which help slow the breakdown of blood clots and subsequent excessive bleeding. The preliminary data also suggested that fewer patients receiving the drug experienced serious bleeding events.