Four deaths from liver failure linked to a new antibiotic have renewed concerns about the nation’s drug safety program, leading some experts to question the effectiveness of internal fixes made at the Food and Drug Administration since the withdrawal of the discredited painkiller Vioxx.
“This is another example that we should see as a signal that the current system needs reform,” said Arthur Levin, director of the Center for Medical Consumers, a New York-based advocacy group, and a member of the FDA’s drug safety advisory committee.
“It’s not about the FDA not doing it’s job it’s that the process we have in place, and the authority the FDA has at present, simply aren’t up to the task,” he said.
Marketed as Ketek, the antibiotic linked to the liver deaths was approved in 2004 as a treatment for serious respiratory infections that have become increasingly resistant to older drugs.
At the time, government regulators recognized the potential for liver damage but concluded that the risk was about the same as for other antibacterial drugs.
After Vioxx was linked to higher rates of heart attacks and strokes and removed from sale in 2004, the FDA set up an in-house drug safety board and pledged to improve communication about emerging problems.
Critics say the agency needs a stronger, more independent safety office, additional funding, better databases and new legal powers to compel manufacturers to track adverse drug reactions.
Doctors in North Carolina were the first to raise concerns about Ketek. They submitted an article to the Annals of Internal Medicine, reporting three cases of acute liver failure in previously healthy patients who had taken the drug.
In January, the journal put an “early release” version of their findings on its Web site and followed up with a fuller article in the print edition two months later.
Drug reactions account for more than half of all cases of liver failure, a medical catastrophe that is otherwise extremely rare and in these cases, the doctors discovered, Ketek was the common denominator.
A May 16 internal memo by FDA safety investigators suggested that the problems with Ketek may be more serious than those identified in the journal article.
In the memo, a copy of which was reviewed by the Los Angeles Times, investigators described a total of 12 cases of liver failure among Ketek patients.
Four patients died, and one required a liver transplant. One patient had taken only a single dose of the drug before becoming ill.
The FDA investigators also compared data on three similar drugs and found that liver failure in patients taking Ketek although rare occurred at much higher rates than in patients taking the other medications.
The investigators recommended that the agency issue its strongest possible warning for Ketek an action that would likely lead to severely restricted use of the drug, which is manufactured by Sanofi-Aventis.
More than 5 million prescriptions for Ketek have been written since it received FDA approval.
The company defends the drug and said it was cooperating fully with the FDA to address any new advice to doctors.
An FDA spokeswoman said the agency has reached no decision. “There is an ongoing investigation looking into the safety of this drug, and we have made clear that, if the data warrant changes we will make them,” said Susan Bro.
The FDA issued a public health advisory when the medical journal article was published, urging doctors to closely monitor patients for signs of liver problems.
The case is already prompting calls for more demanding standards in the approval of new antibiotics. The standard now is that drug-makers must demonstrate that a new antibiotic is not inferior to an older one.
Further complicating the controversy is a separate FDA investigation into scientific fraud in a large safety study of Ketek.
Criminal investigators from the agency discovered “serious data integrity problems” including a fictitious patient, tests performed too late to be of use, and “suspiciously similar” results for multiple patients, according to a 2004 FDA memo reviewed by the Times.