Within the ITT and safety population, demographic and baseline characteristics of both treatment groups

were similar (Table 1). More individuals in the rifaximin group completed the 14-day treatment phase (88 of 106 patients; 83%) compared with those in the placebo group (69 of 104 patients; 66%; Figure 1). A dosing compliance rate of ≥70% was achieved by 98% of individuals in each treatment group. The percentage of participants who took concomitant medications during the study was similar in the rifaximin and placebo treatment groups (76% vs 79%, respectively). Primary and secondary end point analyses were evaluated for the modified ITT population. For the primary end point, prophylactic treatment with rifaximin 600 mg/d for 14 days significantly reduced the risk of developing TD versus placebo (p < 0.0001; Figure 2). Specifically, at the end of the Quizartinib clinical trial FG-4592 14-day treatment period, the cumulative occurrence of TD was 15% in the rifaximin group (15 of 99 patients) compared with 47% in the placebo group (48 of 102 patients). The

hazard ratio indicated that the relative risk of developing TD was 0.27 (95% CI, 0.15–0.49) for the rifaximin group, equivalent to approximately one occurrence in four for individuals in the rifaximin group. Secondary end point analyses demonstrated that a significantly smaller percentage of individuals who received rifaximin developed TD (20%) compared with those who received placebo (48%; p < 0.0001; Figure 3). A smaller percentage of individuals who developed TD in the rifaximin group received rescue therapy compared with placebo (14%

vs 32%, Cediranib (AZD2171) respectively; p = 0.003). Additionally, a smaller percentage of individuals who received rifaximin developed TD associated with diarrheagenic E coli (ETEC or EAEC) compared with placebo (9% vs 18%, respectively), although the difference was not significant (p = 0.098). TD was not associated with invasive bacterial pathogens (Campylobacter, Shigella, or Salmonella) in any individual. The percentage of individuals who developed TD associated with unidentified pathogens was significantly lower in the rifaximin versus placebo group (11% vs 30%, respectively; p = 0.01). A greater percentage of individuals who received rifaximin completed the 14-day treatment period without developing TD (76%) versus those who received placebo (51%; p = 0.0004). The percentage of patients who experienced mild diarrhea but did not develop TD was similar between rifaximin and placebo groups (29% rifaximin vs 21% placebo). During the 7-day post-treatment period, the percentage of participants who developed TD was similar for rifaximin (16%) versus placebo (15%).