276. Comparative Clinical Effectiveness of Fidaxomicin for the Treatment of Clostridium difficile Infection
Session: Poster Abstract Session: Antimicrobial Therapy: Clinical Studies
Friday, October 21, 2011
Room: Poster Hall B1

Background: Clostridium difficile infection (CDI) causes significant morbidity and mortality, with at least $1 billion dollars in healthcare costs annually in the United States. Current treatment options are limited both metronidazole and vancomycin have high rates of recurrence. Possible selection for vancomycin-resistant enterococcus (VRE) is an additional concern. Fidaxomicin is a selective antibiotic under development for the treatment of CDI. Clinical studies have shown that fidaxomicin has a lower rate of CDI recurrence and VRE colonization compared to vancomycin.

Methods: We created a Markov model that simulates the natural history of CDI for a cohort of 10,000 patients entering a hospital over 1 year. We compared clinical outcomes for 4 treatments: (1) fidaxomicin for both initial episode and first recurrence; (2) metronidazole for initial episode and first recurrence; (3) metronidazole for initial episode and vancomycin for first recurrence; (4) vancomycin for initial episode and first recurrence. Outcomes included number of recurrent CDI episodes, episodes of VRE colonization and infection, and CDI-related deaths.

Results: Based on a systematic review of the literature and expert validation, we estimated a risk of recurrence of 15% for fidaxomicin, 27% for metronidazole and 24% for vancomycin. We also estimated a 7% risk of VRE colonization for fidaxomicin, 14% for metronidazole, and 19% for vancomycin. Results for different treatments are as follows:

Number of cases (%) avoided with use of fidaxomicin compared to:

Metronidazole (metronidazole for recurrence)

Metronidazole (vancomycin for recurrence)

Vancomycin (vancomycin for recurrence)

CDI recurrences

15.2 (48.4)

16.2 (50.0)

12.6 (43.8)

VRE colonization

6.4 (52.8)

7.0 (54.9)

9.4 (62.2)

VRE infections

0.9 (52.8)

1.0 (54.9)

1.3 (62.2)

CDI-related deaths

0.6 (13.4)

0.7 (14.2%)

0.5 (11.4%)

Conclusion: First-line therapy with fidaxomicin results in lower rates of CDI recurrences, VRE colonization, VRE infections, and CDI-related deaths compared to metronidazole and vancomycin. The value of fidaxomicin will be further evaluated by comparing the costs of each treatment strategy against the health and economic benefits.

Subject Category: N. Hospital-acquired and surgical infections, infection control, and health outcomes including general public health and health services research

Courtney A. Gidengil, MD, MPH1,2, Mark Hanson, PhD3, Richard Hillestad, PhD3, John Caloyeras, BA3 and Soeren Mattke, MD, DSc2, (1)Infectious Diseases, Children's Hospital Boston, Boston, MA, (2)RAND Corporation, Boston, MA, (3)RAND Corporation, Santa Monica, CA


C. A. Gidengil, Optimer Pharmaceuticals: Research Contractor, Research grant

M. Hanson, Optimer Pharmaceuticals: Research Contractor, Research grant

R. Hillestad, Optimer Pharmaceuticals: Research Contractor, Research grant

J. Caloyeras, Optimer Pharmaceuticals: Research Contractor, Research grant

S. Mattke, Optimer Pharmaceuticals: Research Contractor, Research grant

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