(381) Cost-effectiveness of VOWST (fecal microbiota spores, live-brpk; VOS, formerly SER-109) for Prevention of Recurrent Clostridioides difficile Infection in the United States (US)

Background: : Clostridioides difficile infection (CDI) may result in debilitating, potentially life-threatening complications. VOS is the first FDA-approved orally administered microbiome treatment indicated for prevention of recurrent CDI (rCDI) following antibiotics treatment of rCDI in patients 18 years of age and older. Results of a recent budget impact analysis suggest VOS is cost saving to a United States (US) health plan.

Objective: : To assess the cost-effectiveness of VOS for the prevention of rCDI from a US perspective.

Methods: : A cost-effectiveness model with a Markov structure over a 1-year time horizon was developed in Microsoft Excel comparing VOS versus antibiotics alone and versus Rebyota (RBL, formerly RBX2660). Baseline recurrence risks were obtained from published literature while reduction in recurrence risk with VOS and with RBX come from published randomized clinical trials. Treatment and recurrence costs and quality of life parameters were obtained from published literature. Recurrences, deaths, quality-adjusted life-years (QALY), and costs (in 2025 US dollars) were estimated from a third-party commercial payer perspective and from a Medicare perspective. Incremental cost-effectiveness ratios were calculated. One-way deterministic sensitivity analyses (OWSA) and multivariate probabilistic sensitivity analyses (PSA) were conducted.

Results: : In the Medicare setting, the base-case analysis found treating with VOS was estimated to result in $38,531 in total direct medical costs and 0.78 QALY per patient, compared with $39,919 and 0.73 for RBL, and $41,935 and 0.66 for antibiotics alone. As such, VOS was more effective and less costly (i.e., the dominant strategy) compared with either RBL or antibiotics alone. Results were similar for a commercial population. The OWSA found that the estimated relative risk reduction compared with antibiotics alone and the baseline risk of recurrence were the most influential parameters. However, only at the lower bound of relative risk reduction for VOWST did VOWST cease being cost-effective. In the PSA at a willingness-to-pay threshold of $100,000/QALY, VOS was the dominant strategy in 62% of simulations and cost-effective in 78% of simulations.

Conclusions: : Treatment with VOS has been shown to significantly reduce recurrences for patients with rCDI compared to antibiotics alone. This study illustrates that VOS is a cost-saving and cost-effective treatment compared with antibiotics alone and with RBX. As such, VOS provides clinical and economic value compared with available treatments for rCDI in the US.

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