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‘Follow-on’ rifaximin reduces CDI recurrence, effect estimate lacks precision
Taking rifaximin following initial treatment for Clostridium difficile infection helped patients prevent recurrent disease, according to research published in Gut.
Robin C. Spiller, MB, BChir, MSc, MD, Cantab, FRCP, of the Nottingham Digestive Diseases Centre, in the United Kingdom, and colleagues wrote that a previous study suggested this “follow-on” therapy immediately after CDI resolution helped reduce recurrence. Their aim was to assess its efficacy in a parallel group, randomized controlled trial.
“Theoretically, rifaximin should suppress C. difficile proliferation while commensals recover to re-establish an environment hostile to the pathogen,” they wrote. “Studies in hepatic encephalopathy, colitis and irritable bowel syndrome support this by showing little overall impact of regular rifaximin on the fecal microbiota.”
Investigators recruited 130 patients (mean age, 71.9 years) immediately after they resolved their CDI through treatment with metronidazole or vancomycin. They randomly assigned patients to receive either 400 mg of rifaximin three times a day for two weeks, reduced to 200 mg three times a day for another two weeks (n = 69) or an identical course of placebo (n = 61).
Spiller and colleagues found that the recurrence rate within 12 weeks was lower in the rifaximin group (15.9%) compared with the placebo group (29.5%; difference 13.7%; 95% CI, –28% to 0.7%). The risk ratio was 0.54 (95% CI, 0.28–1.05).
The researchers wrote that the estimated effect of rifaximin lacks precision because they failed to reach their recruitment target.
When they combined their findings with a previous rifaximin study (n = 68) in a meta-analysis, Spiller and colleagues found that the drug produced an overall absolute reduction in risk of CDI recurrence of 14% (95% CI, –28% to –3%).
“The results of this trial are consistent with the earlier study suggesting that rifaximin treatment after resolution of C. difficile-associated diarrhea with standard therapy may reduce the risk of recurrence. However, like the earlier trial, the CI was wide and does not rule out no effect of rifaximin,” the researchers wrote. “However, combining our data with the earlier trial in a meta-analysis shows a significant reduction in CDI recurrence of around 50%. This provides some evidence for its efficacy, but larger trials are needed before the true effect size can be accurately estimated.” – by Alex Young
Disclosures: Spiller reports that he received the rifaximin and matching placebo free of charge from Norgine Pharmaceuticals. All other authors report no relevant financial disclosures.