“The severity may be limited simply because the drug exposure is quite short,” Dr. Lee said.
Sanofi maintained that the hepatotoxicity was similar to that of other antibiotics. The panel was split on whether Ketek was an outlier.
Committee members were more concerned about exacerbations of myasthenia gravis, a neurologic condition affecting about 35,000–70,000 Americans. Many individuals aren't aware they have the condition and might unwittingly take Ketek. The FDA's review found 33 reports of exacerbations of myasthenia gravis since 2004. Of those, seven were life threatening. Twelve patients required a ventilator or intubation.
There were 71 cases of vision disorders and 23 cases of disturbances in consciousness with serious outcomes. In one case, an 18-year-old passed out while driving and struck and killed a pedestrian.
Sanofi-Aventis stuck to its data showing that Ketek was no different from other drugs in the class. “Overall, we believe that the safety risks with telithromycin appear to be similar to widely prescribed antibiotics,” said Dr. Bruno Leroy, head of the company's internal medicine franchise.
Some FDA staffers were not convinced. “Ketek stands out among the macrolides in its unique and notable toxicity,” said Dr. Rosemary Johann-Liang, deputy director of the division of drug risk evaluation at FDA's Center for Drug Evaluation and Research.
Ketek has been prescribed to 6 million U.S. patients since 2004, according to Sanofi-Aventis.