Antibiotic causes liver damage
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UPDATE 3-Sanofi adds new liver warning to antibiotic label
Thu Jun 29, 2006 8:02 PM ET
(Adds additional FDA comment paragraph 5, sales figures paragraph 11, more warning information 14)
By Lisa Richwine
WASHINGTON, June 29 (Reuters) - Sanofi-Aventis put a stronger warning on its antibiotic Ketek following the deaths of four patients who took the drug and developed liver failure, U.S. regulators said on Thursday.
Liver failure also was reported in eight other Ketek users, including one who needed a liver transplant, the Food and Drug Administration said. Twenty-three others developed less serious liver damage, the FDA said.
FDA officials said the liver problems were rare and a known complication of other antibiotics. Ketek was approved in 2004 to treat certain types of sinusitis, bronchitis and pneumonia including cases that resist other antibiotics.
"You are looking at a playing field where all the drugs used to treat these conditions have the potential for serious adverse events. Given what we know today, we believe the benefits of Ketek outweigh the potential risk" when used according to prescribing instructions, said Dr. John Jenkins, director of the FDA's Office of New Drugs.
With current information, "we cannot definitely conclude the risk is greater than the risks of other antibiotics" used for the same infections, Jenkins added.
The new, bold-faced warning on Ketek's label advises doctors and patients to watch for signs of liver problems and stop taking Ketek if they appear. Symptoms can include fatigue, malaise, loss of appetite, nausea, yellow skin and dark urine.
"In certain of these cases, it appears that there are no other likely causes of the liver injury, so it does appear they were due to use of the drug," Jenkins said.
FDA officials estimated the rate of reported liver problems was about 23 per 10 million prescriptions through April 2006.
They cautioned, however, that the figure did not give a true picture of the risk because it was likely there were more unreported cases. Plus, it is unknown how many patients actually took the drug they were prescribed.
"FDA will continue to evaluate Ketek-associated safety issues and take further actions if warranted," an agency statement said.
Ketek's U.S. sales for the first half of 2006 are estimated at $50 million, Sanofi said.
The company said it also believed Ketek, known generically as telithromycin, offered important benefits.
"Based on the in-depth review of the clinical trial and post-marketing data, we continue to believe that the benefits of Ketek outweigh the risks when the drug is used as directed," said Dr. Sol Rajfer, president of science and medical affairs at Sanofi-Aventis U.S.
Sanofi also updated a warning that Ketek may exacerbate a neuromuscular disorder called myasthenia gravis and cause respiratory failure. The FDA said it had three reports of Ketek patients with that disease who died. Patients with the condition should avoid Ketek unless there are no alternatives, Sanofi said.
The Ketek case has drawn the attention of Senate Finance Committee Chairman Charles Grassley, a vocal FDA critic who has questioned whether the agency dismissed problems with a major Ketek trial in which several doctors were investigated and one was jailed for fraud.
"There are questions about whether this drug should stay on the market, and there's great legitimacy to those questions. Ketek is another example where the FDA accommodated a drug maker and turned a blind eye to serious safety concerns," said Grassley, an Iowa Republican.
Sanofi shares closed up $2.24, or 4.9 percent, at $48.17 on the New York Stock Exchange on Thursday amid a broad market rally. (Additional reporting by Bill Berkrot in New York)