A U.S. government advisory panel is looking into the controversial antibiotic Ketek, which has been linked with liver problems and driving accidents.

The Food and Drug Administration panel will meet Thursday and Friday as the drug's supporters — maker Sanofi-Aventis and the FDA staff who approved it — defend its utility and safety, while U.S. Republican Senator Chuck Grassley has questioned the studies used to approve the drug.

The panel will consider the costs and benefits of the drug, which was approved in 2004. It has been used to treat 28 million people internationally, including six million in the U.S., the company said.

Ketek, the brand name for telithromycin, is used to treat some types of pneumonia, throat and sinus infections, and exacerbation of chronic bronchitis.

Concerns about Ketek arose after the Annals of Internal Medicine published a report in January outlining three cases of liver problems resulting from the drug. 

A report prepared by FDA staff for the meeting this week said that as of April, "adverse event reports associated with telithromycin" identified 110 "liver events," including 12 cases of acute liver failure and 23 cases of acute serious liver injury. The cases resulted in four deaths and one liver transplant.

The study also said that the reported rates of liver problems increased between 2005 and 2006, which is "a concern," and there are also issues with visual disorders and loss of consciousness. The FDA studied those, and concluded that there were 94 cases that may have been linked to Ketek.

There were no deaths among the patients, but in one case, a driver lost consciousness and killed a pedestrian.

The FDA report recommended that drivers and heavy-equipment operators be warned about the possible problems, and the company "develop a plan to inform and educate prescribers regarding these risks. Also, consideration should be given for the development of a medication guide to be provided to patients when telithromycin is dispensed."

Sanofi said the risks associated with telithromycin appear to be comparable with those of other antibiotics used to treat the same problems.

Sanofi added a liver warning to Ketek in the summer, and Health Canada and the company have warned users to be careful.

'Data integrity problems': FDA

Senator Grassley has said that he was alarmed because the FDA used an Aventis study "riddled with fraudulent information" to approve Ketek.

A U.S. doctor, Maria Anne Kirkman-Campbell, was sentenced in March 2004 to 57 months in prison, fined $557,251.22 US and told to reimburse Aventis for $925,774.61 US for fraud related to a Ketek study, the FDA said in a letter to her.

In its briefing material for the meeting, FDA staff said "data integrity problems with some investigators in study 3014, coupled with systematic problems in trial monitoring, led to the conclusion that the study could not be relied upon to take a regulatory action."

Instead, the  FDA "augmented its understanding of safety from clinical trials with post-marketing experience in four million European and Latin American patients to conclude there was substantial evidence of safety."