Experts back new drug for diarrhea-causing bacterial infection

An antibiotic developed by a San Diego firm received a government panel's backing as a treatment for diarrhea caused by increasingly common bacterial infections often acquired in hospitals and nursing homes.

The panel of outside experts convened by the Food and Drug Administration voted 13 to 0 that fidaxomicin, marketed under the trade name Dificid by Optimer Pharmaceuticals Inc., is safe and effective in combating symptoms associated with Clostridium difficile, also known as C. diff.

The unanimous vote endorsed the FDA's preliminary findings and increases the chances that the agency will approve fidaxomicin. The FDA, which is expected to make a decision by May 30, is not required to follow the recommendations of its advisory panels, but it usually does.

The advisory panel split 6 to 6, with one abstention, on whether fidaxomicin was effective in reducing the recurrence of C. diff infection-related diarrhea.

Optimer Vice President John Prunty said the split vote reflected uncertainty over how the FDA worded a question about the issue and not doubt about fidaxomicin's superiority in preventing the recurrence of diarrhea.

Fidaxomicin's medical value may turn on its effectiveness to prevent recurrences, said Neil Fishman, director of the antimicrobial management program for the University of Pennsylvania Health System.

Research showed that patients treated with fidaxomicin suffered recurrences in 15% of cases, compared with 25% for the FDA-approved drug vancomycin, Fishman said. That's important, he said, because if a patient has one recurrence, he or she has a 50% chance of getting a C. diff infection a third time, and successive cases require longer treatment.

If approved, fidaxomicin would join vancomycin as the only FDA-approved treatments for C. diff. In practice, at least one other antibiotic, metronidazole, also is used to treat the infections.

The Centers for Disease Control doesn't track C. diff specifically, but according to the Society for Healthcare Epidemiology of America, it's the most commonly recognized cause of infectious diarrhea in healthcare settings.

"C. diff definitely is on the increase," said Richard Dwyer, a gastroenterologist at Hollywood Presbyterian Medical Center in Los Angeles.

The increase may be linked to overuse of antibiotics, which can kill beneficial bacteria and cause pathogens to develop resistance, Dwyer said.

C. diff infections tend to strike patients who already are on certain antibiotics, including fluoroquinolones and cephalosporins.

Those antibiotics suppress bacteria that would normally keep C. diff in check, allowing it to become established in the gut, where it can cause severe diarrhea leading to dehydration, kidney failure and in some cases death.

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