Common C Difficile Meds Have Similar Outcomes for Severe Infections

Investigators hope their findings will alleviate clinicians’ concerns about choosing between fidaxomicin and oral vancomycin for treatment.

Chris Gentry, PharmD

Treatment with fidaxomicin and oral vancomycin showed similar outcomes in patients with severe cases of Clostridium difficile (C difficile) infection, according to a recent report.

Investigators from the Oklahoma City VA conducted a retrospective study including patients treated with both courses in order to compare clinical outcomes of fidaxomicin and oral vancomycin treatment in severe cases of C difficile infection. The study authors said that improving treatment outcomes for C difficile infection is a great need, and that there are still questions regarding cost effectiveness and the role adjunctive therapy can play in reaching these goals.

There were 213 patients treated with fidaxomicin identified during the study period of 2011 to 2017 and the investigators also found 639 patients treated with oral vancomycin. All of the patients in the study were veterans and only their first severe C difficile infection episode was included.

The investigators did not find any statistically significant differences between the 2 groups for the primary outcome in combined clinical failure, or recurrence rates, they said.

“I was not expecting the difference seen in conversions of fidaxomicin patients to vancomycin vs. vancomycin patients to fidaxomicin (8.9% vs <1%, respectively),” study author Chris Gentry, PharmD, told MD Magazine®. “We controlled for any conversions due to formulary restriction by excluding any conversions within 72 hours of starting therapy, so all of these conversions happened [well] into the patients’ treatment course and would have little chance of being due to restriction denials.”

Conversions from one drug to the other, or the addition of metronidazole after the first 72 hours of therapy was considered a clinical failure to the investigators, they said.

All-cause mortality was the same in both groups at 30, 90, and 180 days, the investigators reported. Additionally, recurrence rates were identical between the 2 groups.

“Some clinicians might be surprised that fidaxomicin and vancomycin had similar recurrence rates, given the phase 3 trial of (primarily) mild to moderate C difficile infection demonstrating lower recurrence rates with fidaxomicin,” Gentry continued. “We have seen mixed results with subsequent data, though, so I can’t say that I’m surprised by the similar recurrence rates.”

The study authors wrote that there were few comparisons between these 2 treatment options in the available literature, but regardless, the 2017 IDSA/SHEA treatment guidelines added fidaxomicin to oral vancomycin as a choice for treating severe episodes of C difficile infection. These recommendations, they said, were based on what appeared to be just a few randomized clinical trials.

“I think this data provides some confirmation of the recent IDSA guideline recommendations to choose either agent for the treatment of severe C difficile infection, and it perhaps alleviates some clinicians’ concerns over whether vancomycin might be inferior to fidaxomicin in this population (it does not appear to be),” Gentry said. “It also reiterates to the clinician the unfortunate and unacceptable outcomes of these patients suffering from severe C difficile infection; 24% recurrence rates and 11% 30-day overall mortality rate.”

The paper, “Fidaxomicin versus oral vancomycin for severe Clostridium difficile infection: a retrospective cohort study,” was published in Clinical Microbiology and Infection.