FDA panel splits on pair of antibiotics

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COLLEGE PARK, Md. (AP) -- Federal health advisers on Wednesday backed the benefits of an experimental antibiotic but rebuffed another, questioning whether it would be able to fight dangerous staph infections that are becoming increasingly common.

A panel of infection experts assembled by the Food and Drug Administration voted 21 to 5 in favor of the safety and effectiveness of an injectable drug from Theravance, despite concerns it could cause birth defects. Panelists narrowly sided against a similar product from rival Targanta Therapeutics, saying the company's studies were too small and too old to show the drug's effectiveness against some recent bacterial strains.

The Food and Drug Administration is reviewing both treatments for patients with hard-to-treat skin infections caused by drug-resistant bacteria. The agency is not required to follow the advice of its panelists, though it usually does.

In recent decades, some varieties of germs have grown immune to popular antibiotics like penicillin, creating demand for a new generation of medications.

About 95,000 serious infections and 20,000 deaths due to drug-resistant staph bacteria occur in the U.S. each year. These superbugs have traditionally been spread through hospitals and doctors' offices, but there have been recent outbreaks at schools, raising concern about the dwindling number of new antibiotics available.

While most infections cause only mild skin irritation, the more powerful strains can enter the bloodstream, destroy flesh and become lethal.

Two studies conducted by Theravance showed that its drug telavancin, a once-daily injection, was at least as effective as the strongest antibiotic now on the market, vancomycin. While vancomycin is still the standard of care for life-threatening infections, some bacteria have recently developed resistance to it.

Acknowledging the need for new bacteria-fighting options, the FDA panel backed Theravance's treatment, despite some evidence of birth defects from animal studies.

Panelists voted 18 to 5 that there were certain medical situations when the drug's benefits would outweigh its risks for pregnant women. Three panelists abstained from voting.

"In order to save a life, no one would hesitate to use this drug," said Dr. Barth Reller, a professor at Duke University Medical Center. "I just don't think it should be given to pregnant women unless one has exhausted all other options."

While panelists found few safety concerns with Cambridge, Mass.-based Targanta's oritavancin, several complained the company's studies did not demonstrate effectiveness against the most hard-to-treat infections.

The company's two patient trials were conducted between 1998 and 2003, before the prevalance of the most virulent strains of staph bacteria. Panelists voted 10 to 8 against the overall safety and effectiveness of the drug, adding that the small number of patients in one company study also hurt its application.

"People want an effective drug, but we just haven't seen enough evidence here with regard to the contemporary problem," said Reller, who chaired the panel. "The consistent message is we need more evidence to be comfortable on the question of the effectiveness of this drug."

Targanta Chief Executive Mark Leuchtenberger said the company would continue working with FDA to address questions raised by its experts.

"We're disappointed by what we view as a split decision; It certainly makes the road forward steep," Leuchtenberger said.

The FDA is scheduled to decide on Targanta's application early next month. The agency has not set a formal date for Theravance's drug, but a ruling is expected in coming months.

Theravance shares rose 12 cents to $6.85 on Wednesday. Targanta shares rose 75 cents, or 10.7 percent, to $7.75, though trading closed before the panel made its decision.

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