FDA regulators said that Bayer's injectable Trasylol, used to control bleeding in bypass surgery, raised the risk of kidney damage in clinical studies and may also increase the chance of death in patients.
The findings may require restrictions on the use of Trasylol or new clinical trials, according to a posting to the FDA's Web site.
A panel of heart and kidney disease experts is scheduled to consider the information on Trasylol when it meets on Sept. 12.
The FDA held a similar meeting concerning the drug last September after which Bayer said two employees decided to withhold additional information about Trasylol's side effects. The information not provided by Bayer showed that patients on Trasylol had a higher risk of death, kidney failure, congestive heart failure and stroke, the FDA said.
Bayer said last week that an outside investigation concluded the employees did not intend to mislead regulators.
Bayer said in a published report that it has since revamped how it handles drug studies. Meanwhile, the two employees, based in Germany, were suspended for failing to inform supervisors that the study was completed, a spokeswoman for the company told Bloomberg.com.
Annual sales of Trasylol fell 33% to $195 million in 2006 compared with the year earlier period.