By Ed Susman
SAN FRANCISCO -- September 15, 2009 -- Treatment of Clostridium difficile-caused diarrhoea with the investigative drug fidaxomicin appears to prevent relapses better than treatment with oral vancomycin, researchers stated here at the 49th Annual Interscience Conference on Antimicrobial Agents and Chemotherapy (ICAAC).
"Of the patients in the per protocol population who were cured, 13.3% of patients in the fidaxomicin group and 24% of the vancomycin group experienced recurrence," said Yoav Golan, MD, Tufts Medical Center, Boston, Massachusetts, in a poster presentation on September 14.
Dr. Golan said the difference between the groups reached statistical significance (P < .01) in favour of fidaxomicin. He noted that the difference in the intention-to-treat patient population followed the same trends in favour of fidaxomicin.
In the phase 3 study, 323 patients were assigned to receive oral vancomycin 4 times a day while 300 patients were assigned to receive oral fidaxomicin twice a day during the 10-day treatment to determine cure or failure of therapy, and then were followed for another 4 weeks to determine recurrence.
"Recent data suggest that C difficile infection recurrence beyond 2 weeks after the completion of initial therapy may be attributed to a new acquisition rather than recurrence," said Dr. Golan. He said that researchers are performing further tests to try and determine if the late recurrences observed in the trial were new infections or true recurrences of the disease.
Dr. Golan said that C difficile infection recurrence was higher among older patients and among those who were hospitalised. "Regardless of treatment assignment," he said, "the use of concomitant antibiotics markedly increased recurrence rates. Recurrence of C difficile infection developed later among those who received fidaxomicin therapy."
"Clostridium difficile infection has become a growing problem in hospitals, long-term care facilities, and in the community," Dr. Golan said. "Current treatment options include metronidazole and oral vancomycin. However, approximately 20% to 35% of C difficile infection patients who initially respond to these treatments experience a recurrence."
In the study, recurrence with oral vancomycin occurred within 10 days in about 14% of patients compared with a recurrence rate of about 3% among those on fidaxomicin, he said. About 20% of oral vancomycin-treated patients recurred within 20 days compared with 9% of the fidaxomicin-treated patients. The difference in both time frames was statistically significant (P < .01), he said.
Funding for this study was provided by Optimer Pharmaceuticals.
[Presentation title: Low Recurrence Rate Among Patients (Pts) With C. difficile Infection (CDI) Treated With Fidaxomicin (FDX). Abstract LI-1639]
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