FDA officials question safety of antibiotic 'Ketek'

Thursday, July 20, 2006

The New York Times reports that safety officials working for the Food and Drug Administration have expressed concerns over the safety of an antibiotic, telithromycin and questioned its approval for use. The drug, marketed under the trade name Ketek, has been widely prescribed since its 2004 FDA approval.

The New York Times reports that David Graham, one of four FDA safety officials concerned about safety of the antibiotic in both adults and children, wrote in an E-mail message to another agency official that the drug's 2004 U.S. approval was in error and should be withdrawn.

The concerns focus on the drug's liver toxicity, but also extends to vision problems and other nervous system effects (reported blackouts) and worsening of symptoms in patients suffering from myasthenia gravis.

The drug has been prescribed more than 5 million times. Liver failure has been reported in fourteen adult patients, four of whom died; another twenty-three sustained "serious liver injury."

In January 2006, after cases of serious liver toxicity were reported in the Annals of Internal Medicine (a professional journal published by the American Medical Association), the FDA issued a public advisory to that effect and, in June, 2006 announced that it had completed its safety assessment and required the manufacturer to add additional warnings about the risks of liver toxicity and for patients with myasthenia gravis to the product labeling.

An F.D.A. spokeswoman, Susan Bro, said, “Every issue or question raised during the Ketek review process and subsequently since approval has been rigorously reviewed by the nation’s best physicians, statisticians and epidemiologists both internal and external to the F.D.A.”

A spokeswoman for drugmaker Sanofi-Aventis announced the drug's safety label has already been modified. "We continue to believe that the benefits of Ketek outweigh the risks when the drug is used as directed for its approved indications," said Dr. Sol Rajfer, president of science and medical affairs of Sanofi-Aventis' U.S. division.

Excerpts of Dr. Graham's internal June 16 memorandum published by the Times reveal strong criticism of the drug's approval. “It’s as if every principle governing the review and approval of new drugs was abandoned or suspended where Telithromycin is concerned,” Dr. Graham wrote. In the document, Graham subsequently advised Telithromycin's "immediate withdrawal" from the U.S. prescription drug market. The Times characterized the internal FDA climate as a "fierce battle," which is most likely fueled by the increased press attention in recent months.

Apart from Dr. Graham, who also voiced safety concerns during the Vioxx scandal, three other F.D.A. officials have been identified as critics of Telithromycin's approval: Dr. Charles Cooper, Dr. David Ross and Dr. Rosemary Johann-Liang. Bipartisan congressional interest has also been triggered. Senator Charles E. Grassley (R-Iowa, chairman, Senate Finance Committee) is "investigating" the issue with Representatives Edward J. Markey (D-Mass) and Henry A. Waxman (D-Calif).

Although The Times claimed to receive more than "dozens" of messages (presumably e-mails), the paper did not disclose the source.