Fidaxomicin Superior to Vancomycin in Reaching Desired C Difficile Outcomes

Erik R. Dubberke, MD

New research observed fidaxomicin is superior to vancomycin in achieving desired clinical outcomes among patients with clostridioides difficile infection (CDI).

In fact, the absolute differences in the clinical outcomes in the current real-world study were similar to those reported in the fidaxomicin randomized trials, noted the investigators.

“Our findings support the 2021 change in clinical guidelines recommending fidaxomicin over vancomycin,” wrote study author Erik R. Dubberke, MD, Washington University in St. Louis.

These data were presented at the 2022 Digestive Disease Week Annual Meeting in San Diego, California.

Despite randomized trials exhibiting superiority of fidaxomicin over vancomycin in achieving sustained response among patients with CDI, there is a lack of real-world data on their comparative effectiveness. This is particularly apparent in a high-risk, high-prevalence population such as Medicare beneficiaries.

As such, the current study looked to compare clinical outcomes (sustained response and CDI recurrence) within 4-weeks and 8-weeks after initial treatment with fidaxomicin versus vancomycin in this patient population.

Investigators performed a retrospective claims-based study using 2016-2018 100% Medicare Parts A, B, and D claims. The population included elderly fee-for-service Medicare beneficiaries receiving fidaxomicin or vancomycin in the initial CDI episode and recurrent CDI episode setting.

The sustained response was defined as having evidence of clinical resolution, defined as no additional treatment or hospitalization before or within one day after the day’s supply of the initial prescription is exhausted and no evidence of CDI recurrence.

Investigators measured CDI recurrence among patients with clinical resolution as any evidence of a new CDI treatment or CDI-related hospitalization within 4 weeks (or 8 weeks) after the initial prescription fill. They used propensity-score (PS) matching as the primary analytic approach.

They noted that before PS-matching, each group was similar in age and race, but the fidaxomicin group was more likely to have risk factors for recurrence compared to the vancomycin group in both samples.

Then, following PS-matching, investigators had a total of 190-matched pairs in the initial CDI episode sample and 67-matched pairs in the recurrent CDI episode sample. Data show in the initial CDI episode sample, fidaxomicin had a 13.5% higher rate of 4-week sustained response compared to vancomycin (71.7% vs 58.2%; P = .0058). Further, there was a 13.2% higher rate observed for 8-week sustained response (63.2% vs 50.0%; P = .0114).

Dubberke noted that rates of CDI recurrence at 4-weeks and 8-weeks for patients with an initial CDI episode were lower for fidaxomicin compared to vancomycin. However, this was not considered statistically significant, which may have been due to sample size.

Data show sustained response at 4 weeks and 8 weeks in the recurrent CDI episode sample had favorable effects with fidaxomicin over vancomycin by 30.1 percentage points (P = .0002) and 27.6 percentage points (P = .0012), respectively.

“Rates of CDI recurrence were also lower for fidaxomicin vs. vancomycin, but not statistically significant,” Dubberke concluded.

The study, “Real-World Comparative Effectiveness of Fidaxomicin Vs. Vancomycin Among Medicare Beneficiaries with Clostridiodes Difficile Infection,” was presented at DDW 2022.