Fidaxomicin, an investigational broad-spectrum antibiotic, is safe and effective for treating Clostridium difficile infections, the FDA’s Anti-Infective Drugs Advisory Committee decided yesterday.

The committee unanimously voted 13-0 in favor of approving fidaxomicin (Dificid, Optimer Pharmaceuticals) to treat C. difficile, a bacteria that can cause severe diarrhea, colitis and even death.

The FDA does not have to follow the recommendations of its advisory panels, but it often does. If approved, fidaxomicin will be the first new antibiotic approved in 30 years to treat C. difficile infections.

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C. difficile affects more than 700,000 people in the United States each year and poses significant problems for hospitals and long-term care facilities, according to a press release.

The panel based its decision on data from two phase-3 clinical trials, which showed that fidaxomicin was noninferior to vancomycin — the only antibiotic currently approved to treat C. difficile — and may be better at preventing recurrent infections with certain strains of the bacteria.

About 20% to 30% of patients that respond to treatment with oral vancomycin or off-label metronidazole experience a recurrence.

In one of the studies reviewed by the advisory committee, researchers enrolled 629 patients from sites in the United States and Canada, and randomly assigned patients to either fidaxomicin 200 mg twice daily for 10 days or vancomycin 125 mg four time daily for 10 days.

Patients in both groups met study endpoints for clinical cure, defined as no diarrhea and no need for further treatment two days after the last episode of diarrhea, at similar rates — 88.2% of patients in the fidaxomicin group vs. 85.5% of patients in the vancomycin group. Furthermore, patients in the fidaxomicin group had fewer recurrences at 30 days compared with those in the vancomycin group (15.4% vs. 25.3%, P=0.005).

Outcomes from the second trial, which involved 735 patients from the United States and Europe, were similar for clinical cure (87% for fidaxomicin vs. 85% for vancomycin) and likelihood of recurrence.

Despite these findings, the committee members were undecided on the role that fidaxomicin should play in treating recurrences. They said that the evidence was inconclusive as to whether the drug should be indicated specifically for this treatment because the 30-day time frame allotted for recurrences may not be long enough.