Outcomes of Fidaxomicin Treatment of Clostridium difficile Infection

Abstract

Introduction: Fidaxomicin is a narrow spectrum macrocyclic antibiotic used for the treatment of Clostridium difficile infection (CDI). The aim of this study was to evaluate response and recurrence rates of CDI after treatment with fidaxomicin. Methods: All potential cases of CDI treated with fidaxomicin at our institution over a 3-year period were identified using an electronic search of medical records. Criteria for study inclusion included a definite diagnosis of CDI and treatment with fidaxomicin 200 mg twice daily for 10 days. Data collected included demographic information, number of prior CDI episodes, prior CDI treatment, response to fidaxomicin, recurrence after treatment, and medication adverse effects. Response to treatment was defined by the resolution of diarrhea after treatment. In cases where diarrhea did not resolve, a primary non-response was recorded. Recurrent CDI was defined if diagnostic criteria were met within 8 weeks of initial diagnosis after documented symptom resolution. Diarrhea recurring after 8 weeks of resolution was considered a new episode. Results: Twenty-six patients with CDI were treated with fidaxomicin. The median age was 50 years; 62% were female; 31% had concurrent inflammatory bowel disease (IBD). Most patients (85%) had prior episodes of CDI with a median of 2 previous episodes (range: 0-8). All patients had prior treatments for CDI, 89% with metronidazole, and 81% with vancomycin; 70% had previous treatment with both medications. Complete response was noted in 22 patients (85%), while 4 patients (15%) had no response. However, 55% of responders had recurrent CDI within 8 weeks of diarrhea resolution. Responders who did not recur had fewer prior episodes of CDI (median 1; range: 0-3) than patients who recurred (median 2.5; range: 1-8) or had no response to fidaxomicin (median 2; range: 1-8). All patients (n=4) treated with fidaxomicin for a first episode of CDI responded with resolution of diarrhea with no recurrences. All patients with IBD (n=8) responded to fidaxomicin with resolution of diarrhea, although 62% experienced recurrent CDI. There were no adverse events reported with fidaxomicin. Conclusion: Fidaxomicin is effective in treating CDI in clinical practice, including patients with recurrent infection and IBD. All patients treated with fidaxomicin for a first episode of CDI responded with resolution of diarrhea with no recurrences. However, patients with multiple s before treatment with fidaxomicin had a high rate of further recurrences. Disclosure - Dr. Pardi - Served on an advisory board and was paid an honorarium by Cubist.