Early FMT Shows Promise for Preventing Recurrent C difficile

Will Pass

October 06, 2022

Fecal microbiota transplantation (FMT) is safe and highly effective as first-line therapy for patients with first or second Clostridioides difficile infection, according to the first randomized, double-blind, placebo-controlled trial of its kind.

Study enrollment was halted after an interim analysis revealed significantly better outcomes among patients who received vancomycin plus FMT versus vancomycin alone, reported lead author Simon Mark Dahl Baunwall, MD, of Aarhus (Denmark) University Hospital and colleagues in The Lancet Gastroenterology & Hepatology.

The investigators noted that the participants represented a real-world patient population, so the data support FMT "as a necessary, effective first-line option" in routine management of C. difficile infection.

"Previous studies have demonstrated clinical cure rates [with FMT] of up to 92%," Baunwall and colleagues wrote. "Early use of FMT for first or second C. difficile infection has therapeutic potential, but no formal randomized trials to support use of the approach as a first-line therapy have been done."

The present trial, conducted at a university hospital in Denmark, involved 42 adult patients with first or second C. difficile infection. Patients were randomized in a 1:1 ratio to receive either vancomycin alone or vancomycin plus FMT. All patients received 125 mg oral vancomycin four times daily for a minimum of 10 days after diagnosis. On day 1 after completion of vancomycin therapy and again between day 3 and 7, patients received either oral FMT or matching placebo, depending on their group. After completing the protocol, patients were followed for 8 weeks or C. difficile recurrence to evaluate resolution of C. difficile–associated diarrhea.

"In this trial, patients were treated with two sequential FMT procedures on separate days," the investigators noted. "This practice might have overtreated some patients and differs from previous trials. It remains unknown whether optimal effect is achieved by one or two treatments."

The trial design called for 84 patients, but enrollment was halted after an interim analysis of the above cohort of 42 patients because of significantly lower rate resolution in the placebo group. At the 2-month mark, 90% (95% confidence interval, 70%-99%) of patients in the FMT group had resolution, compared with only 33% (95% CI, 15%-57%) of patients in the placebo group (P = .0003), constituting a 57% (95% CI, 33%-81%) absolute risk reduction.

Most patients experienced adverse events, including 20 in the FMT group and all 21 in the placebo group, although most were transient and nonserious. The most common adverse events were diarrhea, which occurred more frequently in the FMT group (23 vs. 14 events), followed by abdominal pain(14 vs. 11 events) and nausea (12 vs. 5 events).

One limitation of the study was its single-center design with regional uptake; the authors noted that, despite having high statistical power for the clinical effect, the study's premature termination and low patient number prevent inferences regarding mortality, time to effect, and cost.

"The results of this trial highlight how the use of fecal microbiota transplantation as a first-line treatment can effectively prevent C. difficile recurrence and suggests that microbiota restoration might be necessary to obtain sustained resolution," the investigators wrote. "At present, only 10% of patients with multiple, recurrent C. difficile infection and indication for FMT receive it. International initiatives address the unmet need, but logistic and regulatory obstacles remain unsolved."

Encouraging Findings, Lingering Concerns

Nicholas Turner, MD, assistant professor in the division of infectious diseases at Duke University, Durham, N.C., praised the study for "pushing the boundaries for FMT," and noted that the methodology appeared sound. Results in the placebo group, however, cast doubt on the generalizability of the findings, he said.

Dr Nicholas Turner

"If you look at the group that received vancomycin plus placebo, their failure rate was really astoundingly high," Turner said in an interview, referring to the 67% failure rate in the control group; he noted previous studies had reported failure rates closer to 10%. "I think that just calls into question just a little bit what happened with that control group."

Turner said his confidence would go "way, way up" if the findings were reproduced in a larger study. Ideally, these future trials would use fidaxomicin, he added, which is becoming the preferred option over vancomycin for treating C. difficile.

Dr John Kao

John Y. Kao, MD, professor of medicine and codirector of the FMT program at University of Michigan Medicine, Ann Arbor, offered a different perspective, suggesting that the control group findings shouldn't overshadow the efficacy of FMT.

"I agree that historical data would tell us that the placebo population should see a much higher response," Kao said in an interview. "In my mind though, the success rate of FMT over placebo is what I would expect. The message of the study should be upheld: that FMT is an effective therapy whether it's given early or, as the way we give it now, as a sort of rescue therapy."

Despite this confidence in FMT as an efficacious first-line option, Kao said it is unlikely to be routinely used in this way anytime soon, even if a larger trial echoes the present results.

"We don't know the long-term risks of FMT therapy, although we've been doing this now probably close to 20 years," Kao said.

Specifically, Kao was most concerned about the long-term risk of colon cancer, as mouse models suggest that microbiome characteristics may affect risk level, and risk may vary based on host-microbiome relationships. In other words, an organism may pose no risk in the gut of the donor, but the same may not be true for the recipient.

While increased rates of colon cancer or other serious illnesses have not been detected in humans who have undergone FMT over the past 2 decades, Kao said that these findings cannot be extrapolated over a patient's entire lifetime, especially for younger individuals.

"In a patient that's 80, you would say, yeah, let's go ahead and treat you [with FMT] as first-line therapy, whereas someone who's 20, and has maybe another 50 or 60 years longevity, you may not want to give FMT as first-line therapy," Kao said.

This study was supported by Innovation Fund Denmark. The investigators disclosed no competing interests. Turner previously performed statistical analyses for a Merck study comparing vancomycin, fidaxomicin, and metronidazole for C. difficile infection. Kao disclosed no relevant conflicts of interest.

This article originally appeared on MDedge.com, part of the Medscape Professional Network.

Comments

3090D553-9492-4563-8681-AD288FA52ACE
Comments on Medscape are moderated and should be professional in tone and on topic. You must declare any conflicts of interest related to your comments and responses. Please see our Commenting Guide for further information. We reserve the right to remove posts at our sole discretion.

processing....