Extended-pulsed fidaxomicin therapy for recurrent Clostridioides difficile infection after standard vancomycin and fidaxomicin failure: A case report.

Clostridioides difficile infection (CDI) is a leading cause of healthcare-associated diarrhea. Recurrence occurs in up to 60 % of patients following multiple episodes, posing a major clinical challenge. While vancomycin (VCM) and fidaxomicin (FDX) are recommended first-line therapies, treatment failures and recurrences are not uncommon. Extended-pulsed fidaxomicin (EPFX) has been proposed to reduce recurrence, especially in high-risk patients, though the evidence remains limited for those with multiple prior relapses. We report the case of a 66-year-old man with advanced esophageal and gastric cancer who experienced four episodes of recurrent CDI despite standard treatment with VCM and FDX. Given the unavailability of bezlotoxumab (BEZ) in Japan and the limited accessibility of fecal microbiota transplantation (FMT), EPFX was selected as a salvage regimen. After both EPFX and pulse-tapered oral VCM were explained, the patient and physician elected to initiate EPFX, consisting of 200 mg twice daily for five days followed by 200 mg every other day for 20 days. No further recurrences were observed for over four months, and no adverse effects were noted. This case supports the use of EPFX in patients with multiple high-risk features-including advanced age, active malignancy, and prior treatment failures-despite the EXTEND trial's exclusion of patients with ≥3 recurrences. The favorable pharmacokinetic properties of FDX may have contributed to its efficacy. Importantly, the patient's medication, nutritional, and oncologic status remained stable throughout treatment, suggesting that EPFX played a pivotal role in achieving remission. EPFX may offer a viable option for patients with recurrent CDI refractory to standard therapies.