Description:
<jats:p> 9067 </jats:p><jats:p> Background: Oncology patients are at risk for infections, including C difficile infection (CDI). Fidaxomicin (FDX) is a novel antibiotic highly specific for C difficile with improved sustained response compared with vancomycin (VAN). Another important clinical outcome of CDI is time to resolution of diarrhea (TTROD), corresponding to the duration of passing unformed bowel movements. Methods: 183 patients with a current diagnosis of cancer were compared to non-cancer patients from a combined population of 1105 subjects with CDI in two phase 3 trials comparing 10 days of treatment with FDX (400 mg/day) or VAN (500 mg/day). Number of unformed bowel movements (UBM) per 24 h was monitored. Response was considered as ≤3 UBM/24 h. Time to resolution of diarrhea was defined as time in hours from the first dose of study drug to the last UBM on the day preceding two days of ≤3 UBM/24 h. Kaplan-Meier survival analysis (K-M) used the log rank test for significance (p<0.05). Results: The response rate at end of treatment was 79.2% for 183 patients with cancer, compared to 88.6% for 922 patients without cancer (p<0.001). Median TTROD was longer by 45 h in patients with cancer than those without. In the VAN treatment group, median TTROD was 65 h longer in patients with cancer vs those without and significant by K-M. In the FDX group, although median TTROD was longer by 20 h in patients with cancer vs those without, the difference was not significant by K-M. For patients with cancer, TTROD was significantly shorter during treatment with FDX than with VAN. Conclusions: Patients with cancer responded more slowly to treatment for CDI than did non-cancer patients; however, resolution of diarrhea was more rapid by 49 h during treatment with FDX than with VAN. [Table: see text] </jats:p>