Conference Coverage

Role of fidaxomicin for C. difficile infection continues to evolve



SAN FRANCISCO– The role of fidaxomicin for treating mild to moderate Clostridium difficile infection is still finding its way, according to Sarah Doernberg, MD.

For now, fidaxomicin, a narrow spectrum macrocyclic antibiotic, may be appropriate for those at high risk for relapse and/or those requiring concomitant antibiotics – but its high price tag may be prohibitive.

“I think a lot of centers have taken the fidaxomicin data, which were based on patients with initial infection or a single relapse, and extrapolated it to patients with multiple relapses,” Dr. Doernberg, medical director of adult antimicrobial stewardship at UCSF Medical Center, said at the UCSF Annual Advances in Internal Medicine meeting.

In a recent analysis, researchers collected real-world data on implementation of fidaxomicin for CDI patients at seven hospitals in the United Kingdom (Eur J Clin Microbiol Infect Dis. 2016 Feb;35[2]:251-9). In two hospitals where fidaxomicin was used as the first-line treatment for all primary and recurrent episodes, the recurrence rate reduced from 10.6% to 3.1% and from 16.3% to 3.1%, with a significant difference in 28-day mortality, from 18.2% to 3.1%; (P less than .05) and 17.3% to 6.3% (P less than .05). In the remaining five hospitals that used fidaxomicin in selected patients only, the changes in recurrence rates and mortality were less marked.

Other studies have found that fidaxomicin has a similar cure rate, compared with vancomycin (around 88%) but a lower recurrence rate (13%-15%, compared with 25%-27%, respectively; see N Engl J Med. 2011 Feb 3;364[5]:422-31). However, the general cost for a course is significantly more, compared with metronidazole and vancomycin, making fidaxomicin less cost effective as a first-line agent in most cases (Clin Infect Dis. 2013 Aug 15; 57[4]:555-61).

“Our guidelines recommend it in patients who have a very high risk for relapse who would not be candidates for fecal transplant down the line, which generally means immunocompromised patients,” Dr. Doernberg said.

Additional considerations when treating CDI include stopping unnecessary antibiotics, shortening the antibiotic course, narrowing the antibiotic spectrum, and stopping acid-suppressive medication when possible, especially proton pump inhibitors. “Do no use anti-peristaltic agents until acute symptoms of CDI improve,” she said.

Dr. Doernberg disclosed that she is a consultant for Actelion. She has also conducted prior research studies with Cerexa, Cubist, and Merck.

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