C diff spores
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At MAD-ID 2025, a clear theme emerged showing fidaxomicin as the preferred treatment for Clostridioides difficile infection (CDI) in patients at risk of recurrence. Studies demonstrated fidaxomicin reduces recurrence rates compared to vancomycin in groups including older adults, immunocompromised patients, transplant recipients, and those undergoing chemotherapy. Although the initial cost of fidaxomicin is higher, its use can lead to fewer readmissions and lower overall healthcare costs. Barriers such as cost and formulary restrictions continue to limit its use, highlighting the need for provider education and patient assistance programs to support wider adoption in line with current guidelines.
Advancing C diff Management: Fidaxomicin, Microbiome Therapies, and Stewardship
At MAD-ID 2025, Rachel M Kenney, PharmD, led a session on advancing Clostridioides difficile (C diff) management, focusing on updated treatment guidelines, microbiome-based therapies, and the vital role of antimicrobial stewardship. She emphasized the shift toward fidaxomicin as a first-line therapy despite ongoing challenges with cost and access, and discussed the move away from traditional FMT toward FDA-approved microbiome therapies like Vowst and Rebyota. The session also highlighted pharmacists’ roles in navigating access barriers, selecting appropriate treatments, and implementing stewardship strategies to prevent infection and ensure optimal outcomes.
Fidaxomicin Use Remains Flat Despite Guideline Change for C difficile Treatment
Despite updated 2021 IDSA/SHEA guidelines recommending fidaxomicin as the preferred treatment for CDI, a study presented at MAD-ID 2025 by Dakota Rorie, PharmD, showed its use has remained largely unchanged over the past decade, with only a marginal increase in initial (48% to 49%) and recurrent (52% to 51%) cases. The flat trend is attributed to persistent barriers such as cost, formulary access, and prescriber habits. Rorie noted that fidaxomicin was not added to her institution’s formulary until 2023 and is still perceived by many as prohibitively expensive, despite growing insurance coverage and patient assistance programs. She emphasized the critical role of infectious disease and GI consults, provider education, and proactive pharmacist involvement in encouraging adherence to updated guidelines, pointing to emerging national data that show fidaxomicin’s potential to reduce recurrence and overall healthcare costs.
Oral Vancomycin “Tail” Offers No Added Benefit for CDI Prophylaxis
At MAD-ID 2025, Jiye Park, PharmD, presented a study from Massachusetts General Hospital showing that extending oral vancomycin prophylaxis beyond the end of systemic antibiotic treatment, known as a vancomycin tail, provided no significant benefit in preventing recurrent CDI. Among 163 hospitalized adults with prior CDI, recurrence, hospitalization, and mortality rates were similar between patients who continued vancomycin after antibiotics and those who stopped at the same time. The study also found once-daily dosing to be as effective as twice-daily, leading the institution to change its protocols to favor once-daily dosing. Although the vancomycin tail group had lower mortality rates, the results require cautious interpretation due to possible differences in patient severity. Park emphasized the need for further research, particularly prospective and matched cohort studies, to determine if certain high-risk groups such as immunocompromised patients or those with recent CDI recurrences might benefit from extended prophylaxis.
Fidaxomicin Reduces Recurrence Risk in High-Risk C difficile Infections
At MAD-ID 2025, Alyssa Cox, PharmD, presented a multicenter retrospective study of 176 hospitalized adults showing that fidaxomicin significantly reduces the 90-day recurrence rate of initial CDI by 68.3% compared to vancomycin, with recurrence rates of 7.9% versus 19%. The study focused on high-risk patients including those aged 65 and older, immunosuppressed individuals, and patients with severe infections. Fidaxomicin was also associated with shorter ICU stays and fewer C diff-related 30-day readmissions, supporting current IDSA guidelines that recommend fidaxomicin for initial treatment in high-risk groups. Cox highlighted the potential for cost savings with the upcoming generic availability of fidaxomicin and emphasized the importance of preventing recurrence, especially since prior hospitalization independently increased recurrence risk.
Fidaxomicin Tied to Lower C difficile Recurrence in Immunocompromised Patients
At MAD-ID 2025, Natt Patimavirujh, PharmD, presented a retrospective study from Tampa General Hospital showing that fidaxomicin significantly reduces CDI recurrence compared to oral vancomycin in immunocompromised patients, including solid organ transplant recipients and those undergoing chemotherapy. The study found that 28-day recurrence rates were 5% with fidaxomicin versus 30% with vancomycin, and 90-day recurrence rates were 15% versus 40%, respectively. CDI-related readmissions were also lower with fidaxomicin. Although both drugs are effective, fidaxomicin’s narrower spectrum better preserves the gut microbiome, leading to fewer recurrences. Despite its high cost, which remains a barrier, Tampa General removed restrictions on fidaxomicin use for high-risk patients in 2023 and employs patient assistance programs to improve access, supporting its upfront use to reduce costly recurrences and hospitalizations in this vulnerable population.
