It’s time to rethink your approach to C diff infection

Historically, in an effort to keep costs down, an oral solution was often inexpensively compounded at hospitals or pharmacies.²⁰Firvanq now replaces previous compounding and is approximately $165 for 150 mL of the 50 mg/mL concentration, enough medication to treat the full course of CDI.¹⁹

Fidaxomicin, an oral macrocyclic antibiotic with minimal systemic absorption, was first approved by the US Food and Drug Administration (FDA) for CDI in 2011.²¹ The IDSA guidelines recommend fidaxomicin for initial, and recurrent, cases of CDI as an alternative to vancomycin.¹¹ This recommendation is based on 2 randomized double-blind trials comparing fidaxomicin to standard-dose oral vancomycin for initial or recurrent CDI.^21,22

Pooled data from these 2 similar studies found that fidaxomicin was noninferior (10% noninferiority margin) to vancomycin for the primary outcome of clinical cure.²³ Fidaxomicin was shown to be superior to vancomycin regarding rate of CDI recurrence (relative risk [RR] = 0.61; 95% confidence interval [CI], 0.43-0.87). These results were similar regardless of whether the CDI was an initial or recurrent case.²³

Given the lack of systemic absorption, fidaxomicin is generally very well tolerated. The largest downside to fidaxomicin is its cost, which can be nearly $5000 for a standard 10-day course (vs as little as $165 for oral vancomycin).¹⁹ As a result, oral vancomycin solution is likely the most cost-effective ­therapy for initial cases of CDI.²⁴ In patients with poor medication adherence, ­fidaxomicin offers the advantage of less-frequent dosing (twice daily vs 4 times daily with vancomycin).

For cases of recurrent CDI, when treatment failure occurred with vancomycin, fidaxomicin should be considered as an efficacious alternative. If fidaxomicin is used, it is advisable to verify coverage with the patient’s insurance plan, since prior authorization is frequently required.

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