Fidaxomicin Versus Vancomycin for Clostridioides Difficile Treatment

Concomitant antibiotic (CA) use for infection treatment is a major risk factor for recurrent C difficile infection. One SHEA 2022 study examined whether fidaxomicin or vancomycin would be more beneficial for CA patients.

Clostridioides difficile has a dangerous and expensive disease burden, causing up to half a million infections each year in the US alone. Recurrent C diff infection (CDI) is as common as it is deadly, and antibiotic use for a concurrent non-C diff infection is one of the greatest risk factors.

A study presented this week at the Society for Healthcare Epidemiology of America Conference 2022 (SHEA) sought to compare the efficacy of fidaxomicin versus vancomycin, 2 powerful macrolide antibiotics that treat colitis and diarrhea. Both of these therapies have been found to have similar cure rates and low risk of recurrence, but their efficacy in persons receiving a concomitant antibiotic for a non-C diff infection is unknown.

The investigators, led by presenting author Krishna Rao, MD, MS, conducted a randomized, controlled, open-label trial at the University of Michigan and St. Joseph Mercy hospitals in Ann Arbor, MI. Included in the study were hospitalized CDI patients older than 18 with written consent, >3 unformed stools in 24 hours, and ≥1 qualifying CA with a planned treatment of an infection for ≥5 days after enrollment.

Patients were stratified by intensive care unit (ICU) status, and randomly assigned to either fidaxomicin 200 mg 2 times daily or vancomycin 125 mg 4 times daily for 10 days. If CA was continued for more than 10 days, the study drug was also continued until CA ended.

Clinical cure was defined as resolution of diarrhea for 2 consecutive days, maintained until the end of therapy and for 2 days afterward. Recurrent C difficile infection (rCDI) was defined as recurrent diarrhea with positive CDI tests within 30 days of initial treatment.

From a total of 5101 potential patients, 144 were deemed eligible and randomized for the study. Most participants were younger than 65, on proton pump inhibitors (PPIs), and not in the intensive care unit (ICU). The average CA duration was 18.4 days.

In the intention-to-treat population, clinical cure was 73.0% for fidaxomicin and 62.9% for vancomycin. Recurrent CDI was 3.3% for fidaxomicin and 4.0% for vancomycin. The study authors noted that although more CDI patients receiving CA were cured with fidaxomicin, this finding was not statistically significant.

Overall, recurrence for both fidaxomicin and vancomycin was lower than anticipated, which could be due to this study extending the duration of CDI treatment during CA. The investigators recommended further research to determine whether clinical cure is higher with fidaxomicin than with vancomycin during CA exposure, and whether a longer duration of CDI treatment reduces rCDI.

The study, “Comparison of fidaxomicin to oral vancomycin for the treatment of Clostridioides difficile infection in hospitalized patients” was presented on April 12 during the Society for Healthcare Epidemiology of America Conference 2022 (SHEA).