Is fidaxomicin worth the cost? An economic analysis

Abstract

Background: In May 2011, the Food and Drug Administration approved fidaxomicin for the treatment of Clostridium difficile infection (CDI). It has been found to be noninferior to vancomycin; however, its cost-effectiveness for the treatment of CDI remains undetermined.

Methods: We developed a decision analytic simulation model to determine the economic value of fidaxomicin for CDI treatment from the third-party payer perspective. We looked at CDI treatment in these 3 cases: (1) no fidaxomicin, (2) only fidaxomicin, and (3) fidaxomicin based on strain typing results.

Results: The incremental cost-effectiveness ratio for fidaxomicin based on screening given current conditions was >$43.7 million per quality-adjusted life-year and using only fidaxomicin was dominated (ie, more costly and less effective) by the other 2 treatment strategies explored. The fidaxomicin strategy tended to remain dominated, even at lower costs. With approximately 50% of CDI due to the NAP1/BI/027 strain, a course of fidaxomicin would need to cost ≤$150 to be cost-effective in the treatment of all CDI cases and between $160 and $400 to be cost-effective for those with a non-NAP1/BI/027 strain (ie, treatment based on strain typing).

Conclusions: Given the current cost and NAP1/BI/027 accounting for approximately 50% of isolates, using fidaxomicin as a first-line treatment for CDI is not cost-effective. However, typing and treatment with fidaxomicin based on strain may be more promising depending on the costs of fidaxomicin.

Keywords: Clostridium difficile; cost; economics; fidaxomicin; treatment.

Figure 1.

Model outline. Abbreviation: CDI, Clostridium difficile infection.

Figure 2.

Net benefit region graph identifying the optimal or most effective Clostridium difficile infection treatment strategy with a $50 000 per quality-adjusted life-year (QALY) threshold for various costs of the full course of fidaxomicin when (A) the probability of the NAP1/BI/027 strain varied, and (B) the recurrence rate for the NAP1/BI/027 strain after treatment with fidaxomicin varied. The region shows the treatment strategy that “buys” the most QALYs for $50 000 (this is not necessarily the most cost-effective, ie, does not necessarily have the lowest incremental cost-effectiveness ratio). Abbreviation: CDI, Clostridium difficile infection.