Dec. 14 (Bloomberg) -- Sanofi-Aventis SA told U.S. regulators today that its Ketek antibiotic is an essential treatment for bacterial infections, even though the drug has been linked to liver failure and death in some patients.

Two Food and Drug Administration committees are hosting public meetings today and tomorrow to discuss whether Ketek, used to fight pneumonia, bronchitis and sinusitis, is safe enough to remain on the market. More than 600 cases of liver damage, loss of consciousness and other side effects have been reported since the drug won U.S. approval in April 2004.

The panels may recommend stricter labeling, better doctor and patient education, or more studies to support use of the drug. Sanofi says Ketek, which accounted for $50 million of the company's $14 billion in sales in the first half of 2006, isn't more dangerous than similar antibiotics and provides a more effective weapon against drug-resistant bacteria.

``There's no question that there's some rare risk'' to the liver, Judith Jones, an adjunct professor of pharmacology at Georgetown School of Medicine in Washington, told the panels today on behalf of Sanofi. ``This has been known since prior to approval and has been confirmed. What we need to focus on is what the current question is, and that is, in comparison to what?''

Bold-Faced Advice

Sanofi, France's biggest drugmaker, urged regulators to consider studies that show their drug has similar risks as other drugs used for the same indications such as clarithromycin, sold as Abbott Laboratories' Biaxin XL, or as a generic. Reports of adverse events may be skewed by opinion and differences in how data is compiled.

Sanofi agreed in June to bolster U.S. prescribing information by including a bold-faced warning about the risk of potentially fatal liver damage. A European Medicines Agency panel said last month that Ketek shouldn't be given to patients with a history of liver conditions such as hepatitis or jaundice.

An estimated 28 million people worldwide have taken Ketek since 2001, including about 6 million people in the U.S. The $6 pills, known chemically as telithromycin, are given in 800- milligram doses once a day, for five to 10 days. The drug is approved in the U.S. for use by adults only.

Stricter warnings on Ketek have taken a toll on the number of prescriptions dispensed for the drug in the U.S. Ketek's share of the antibiotic market dropped to 0.8 percent in October from an average of 1.8 percent in 2005, Chris Shibutani, an analyst at JPMorgan in New York, said in a Nov. 20 note to clients.

FDA Analyses

The most recent FDA analyses of adverse events associated with Ketek found that most of the reported side effects were in line with the currently approved warnings, according to staff reviews posted yesterday on the agency's Web site.

The regulators identified 79 reports of liver damage linked to the drug as of April, including four reports of deaths in the U.S., according to the documents. About 390 patients had reported blurred vision and other impairments as of July 7, and 137 patients had some loss of consciousness while taking the drug.

These data will be reviewed by the 11 doctors and scientists on the FDA's panels to review drug safety and anti-infective medicines, and eight consultants to the agency's Center for Drug Evaluation and Research, at the meeting in Silver Spring, Maryland. The agency usually follows its advisers' recommendations, though it isn't required to do so.

Focus of Criticism

Senator Charles Grassley, an Iowa Republican, has made Ketek a focus of criticism against the FDA's safety reviews, saying the agency withheld relevant information when the FDA cleared Ketek for sale.

The FDA ``can't be in the business of misleading the public and hiding the truth,'' Grassley, the chairman of the Senate Finance Committee, said yesterday in an e-mailed statement. ``The integrity of the agency is at stake.''

Grassley asked FDA Commissioner Andrew von Eschenbach in a letter yesterday to respond by Jan. 17 to allegations that members of the agency knowingly used fraudulent safety data to approve Ketek. The agency said yesterday that it was reviewing Grassley's letter and that its initial review of safety data in countries where Ketek had already been introduced supported the conclusion that the drug's benefits outweighed its risks.

American depositary receipts of Paris-based Sanofi, each representing one-half of an ordinary share, rose 9 cents to $45.80 at 4:01 p.m. New York time. In Paris, the shares gained 45 cents to 69.70 euros today.

To contact the reporter on this story: Catherine Larkin in Washington at clarkin4@bloomberg.net.

Last Updated: December 14, 2006 16:38 EST