Resolution ofClostridium difficile–Associated Diarrhea in Patients With Cancer Treated With Fidaxomicin or Vancomycin

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.