Questions Surround Safety of FDA-Approved Antibiotic

Questions have arisen about the FDA's approval of the antibiotic Ketek. The drug, which was released in 2004, can cause liver failure and may have been responsible for at least four deaths.

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RENEE MONTAGNE, host:

There are new questions this morning about whether the antibiotic Ketek should still be on the market. At least four people have died on Ketek since the Food and Drug Administration approved it for sale in 2004. Three weeks ago, the agency changed Ketek's label to include the warning that the drug can cause sudden and rapid liver failure. But internal FDA e-mails obtained by NPR show that at least one prominent drug-safety expert inside the agency believes the drug should be pulled from the market. NPR's Snigdha Prakash joins us now. Good morning.

SNIGDHA PRAKASH reporting:

Good morning, Renee.

MONTAGNE: Now, Ketek is used to treat sinus infections and bronchitis. Why is this so controversial?

PRAKASH: Well, Renee, critics say the FDA approved Ketek even though there were lots of unanswered questions about its safety. The story goes back to 2001. That's when Aventis, the company that makes Ketek, first went to the FDA to have Ketek approved. But the FDA had too many questions about Ketek's effect on the liver, on the heart, and there were vision problems.

It asked Aventis to do the large safety study and the study showed that Ketek was very safe. The only problem was the study was tainted by fraud. The doctor who enrolled the largest number of patients is actually serving time in prison for fabricating data for the study. And there were so many other problems at other places where the drug was being studied that the FDA's Division of Scientific Investigation - that's the agency's internal cops - said none of the study's results could be trusted.

MONTAGNE: So, how did it happen then that Ketek was approved by the FDA? I mean, did it know about this fraud? Did the company do a study again? What happened?

PRAKASH: The FDA did know about the fraud. The company didn't do the study again. The FDA approved Ketek in 2004, at least partly, it now appears, because it was reassured by the company that there weren't any big problems in countries like Italy and France, Germany, Mexico, where Aventis had been selling Ketek for some time and where the drug had been used by some three million people. As you said earlier, though, at least four people in the U.S. have died of liver failure since Ketek came on the market here in 2004.

MONTAGNE: Well, put that in perspective. For any big drug used by lots and lots of people, would this make sense, are - those kind of serious side effects do happen?

PRAKASH: They do happen. All drugs do have risks, but there's a tradeoff between the risks of a drug and its benefits. And critics say the benefits of Ketek just aren't worth the risk of fatal liver failure.

MONTAGNE: So as we said, the FDA has changed the drug label to say that Ketek can cause liver failure, but you're reporting that not everyone at the FDA thinks that's enough. At least one person would like to see it off the market.

PRAKASH: Yes, exactly. We've obtained some internal FDA e-mails that show the debate inside the FDA about Ketek's problems, and one of those e-mails is from a scientist at the FDA's Drug Safety Office. His name is David Graham. Graham compared the number of serious liver problems on Ketek to the problems on three other drugs that have been withdrawn from the market because of those liver problems. The drugs are Rezulin, which was for diabetes, the antibiotic Trovan and a painkiller called Duract. And Graham found that by one very important measure Ketek appears to be more toxic than all but one of those drugs.

I'm reading from his e-mail now. He says, there is strong evidence that Telithromycin, that's Ketek, is as hepatotoxic - toxic for the liver - if not more so than most if not all drugs previously withdrawn from the market. He goes on to say we're flying blind as far as safety goes.

MONTAGNE: And, Snigdha, what's the FDA saying about?

PRAKASH: Well, Renee, the FDA isn't happy that its internal e-mails have been released. Susan Bro, who's a spokeswoman for the agency, sent a us a statement they says it's bad public-health policy to release the e-mails and have this discussion in public. She also said the Ketek data had been rigorously reviewed by the agency.

MONTAGNE: And the company's response?

PRAKASH: The company, Renee, says the drug's benefits outweigh its risks when it's used as directed. The label has been changed to warn of liver failure and the company says it's a safe drug.

MONTAGNE: Thanks very much.

PRAKASH: Thank you, Renee.

MONTAGNE: NPR's Snigdha Prakash.

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