Purpose: Patients with cancer are at increased risk for Clostridium difficile-associated diarrhea (CDAD). Little is known about treatment response.
Patients and methods: Two double-blind trials randomly allocated 1,105 patients with CDAD to fidaxomicin or vancomycin treatment (modified intent-to-treat [mITT]), and 183 of these had cancer. Univariate and multivariate post hoc analyses compared effects of treatment and patient characteristics on cure, recurrence, and sustained response after 4 weeks. Time to resolution of diarrhea (TTROD) was also evaluated.
Results: Patients with cancer had a lower cure rate and longer TTROD than patients without cancer. Recurrence rates were similar. Cure was more likely with fidaxomicin than vancomycin (odds ratio [OR] 2.0; P = .065), recurrence was less likely (OR = 0.37; P = .018), and sustained response more frequent (OR = 2.56; P = .003). Under vancomycin, median TTROD was longer in patients with cancer than in those without (123 v 58 hours; log-rank P < .001). With fidaxomicin, median TTROD was not significantly affected by presence of cancer (74 v 54 hours; log-rank P = .145). In the full mITT population, age, hypoalbuminemia, and cancer were inversely associated with clinical cure by multivariate analysis. Study treatment with vancomycin was a significant predictor of recurrence (P < .001). Within the cancer population, low albumin was negatively and fidaxomicin was positively associated with improved cure.
Conclusion: For patients with cancer, fidaxomicin treatment was superior to vancomycin, resulting in higher cure and sustained response rates, shorter TTROD, and fewer recurrences.
Trial registration: ClinicalTrials.gov NCT00314951 NCT00468728.