(ChemotherapyAdvisor) – Two large Phase 3 trials demonstrated that cancer patients with Clostridium difficile-associated diarrhea (CDAD) had higher clinical cure rates, better sustained response, and lower recurrence when treated with Dificid (fidaxomicin) tablets compared to oral vancomycin, announced Optimer Pharmaceuticals, Inc., San Diego, CA, in their presentation of results from a post-hoc subgroup analysis of the trials. These data were presented at the 22nd European Congress of Clinical Microbiology and Infectious Diseases (ECCMID) in London.
Data analysis was performed on a subset of patients from the two randomized, double-blind, non-inferiority Phase 3 trials. Data was selected from 153 patients with active cancer who had received eight days or more of treatment with 200mg Dificid administered orally twice daily or 125mg of oral vancomycin four times daily for a total of ten days. The primary objective of the trials was to compare the safety and efficacy of a ten-day course of Dificid versus a ten-day course of vancomycin for the treatment of CDAD in adults. Based on these two Phase 3 studies, Dificid received FDA approval in May 2011.
Results of the analysis showed that Dificid was five times more likely than vancomycin to produce a clinical response and three times more likely to lead to a sustained response, while patients treated with vancomycin had a 2.6-fold greater risk of experiencing recurrence. When all endpoints were compared, Dificid provided superior response compared to vancomycin: clinical response (97.3% vs. 87.5%, 95% CI 1.07–23.98; P=0.041), sustained response (83.6% vs. 61.3%, 95% CI 1.50–6.91; P=0.003) and disease recurrence (14.1% vs. 30.0%, 95% CI 0.16–0.89; P=0.025). The overall safety profile was similar between the Dificid and vancomycin treatment groups.