FDA approves first ketolide antibiotic

The Food and Drug Administration's April approval of telithromycin, the first of a new class of antibiotics known as ketolides, has physicians excited about another choice to treat bacterial infections but also concerned that it could worsen the problem of overuse that leads to bacterial resistance.

"It's always helpful to have a range of choices," said Elizabeth Steiner, MD, assistant professor of family medicine at Oregon Health and Science University in Portland. "But we have to be very careful about not overusing it so that we prevent potential resistance problems and not put ourselves in a position of being overly dependent on an antibiotic."

The drug will provide another possibility on the list of effective antibiotic pills for easy outpatient use. This list is under continual threat by emerging bacterial resistance as well as the lack of new options in the pharmaceutical research and development pipeline.

"Bacteria are able to survive because they are able to evolve, and that's why it's so important to have a pipeline of new antibiotics," said Paul Iannini, MD, one of the drug's researchers and a clinical professor of medicine at Yale University School of Medicine. "It really gives us physicians a new choice."

Still, some experts maintained that having one more drug is not a solution to antibiotic resistance.

"It's great that we have new antibiotics coming out to combat bacteria that are resistant to older antibiotics, but the same problems apply," said Jeffrey Linder, MD, MPH, an internist at Brigham and Women's Hospital and Harvard Medical School in Boston. "It needs to be prescribed for only appropriate indications, and if we misuse it, the potential is there for resistance."

There is particular concern because telithromycin has been approved for respiratory tract infections, many of which are already treated inappropriately with other antibiotics.

"Antibiotics get prescribed all the time for viral or self-limiting conditions," said. Dr. Steiner. "[That's] not OK -- no matter which antibiotic it is. This drug may be great, but it doesn't matter if you don't need it."

Those who carried out the trials leading to the drug's approval say, however, that while resistance is possible, as with any antibiotic, it is less likely with this drug because it targets the respiratory tract rather than attacking the whole body.

"It has very little activity against the bacteria that exist in the intestinal flora so that the selection of resistance at sites other than the one you're treating is going to be reduced," said Dr. Iannini, who is also chair of medicine at Danbury Hospital in Connecticut.

And, although the advance is unlikely to be the solution to drug resistance for which so many doctors are hoping, it does represent an unusual event in infectious disease -- the introduction of a new antibiotic agent.

"This is part of the slow trickle of new antibiotics because many of the drug companies are not investing the amount of money they should," said Itzhak Brook, MD, professor of pediatrics and medicine at Georgetown University in Washington, D.C. "We won't see another for a while, and it's good that we're going to have this drug because we're running out of options."

Telithromycin, expected to be on the market this summer, will be manufactured by Aventis Pharmaceuticals under the brand name Ketek. The FDA approved it for the treatment of acute exacerbation of chronic bronchitis, acute bacterial sinusitis, and mild to moderate community-acquired pneumonia, including those infections that may be resistant to other drugs.