- Design
- Multicentre, open-label, randomised non-inferiority trial
- Population
- 299 adults with complicated UTI due to ESBL-producing Enterobacterales, improved after 3–7 days IV
- Primary outcome
- Clinical cure within 4 days after completing treatment
- Effect
- 92.8% vs 95.2%; risk difference −2.47% (95% CI −7.84 to 2.89)
A multicentre, open-label, randomised non-inferiority trial at four Korean hospitals enrolled adults admitted with complicated urinary tract infection caused by ESBL-producing Enterobacterales who had improved after 3 to 7 days of intravenous therapy. Published in Clinical Infectious Diseases on 7 October 2026.
Of 299 patients, 152 switched to oral fosfomycin trometamol 3 g once daily and 147 continued intravenous carbapenem or β-lactam/β-lactamase inhibitor. Clinical cure occurred in 92.8% and 95.2% respectively (risk difference −2.47%, 95% CI −7.84 to 2.89), meeting non-inferiority. Microbiological cure in urine (98.0% vs 96.6%) and blood (97.3% vs 97.5%) was similar, as were safety and 30-day outcomes.
The trial was open-label and the lower bound of the interval allows for a cure rate up to about 8 points worse with fosfomycin. Patients had already improved, so the result does not apply to initial treatment. Fosfomycin susceptibility testing is not done routinely in every laboratory. ESBL-producing organisms are common in Indian hospitals, and carbapenem stewardship is pressing, so this is directly relevant where oral fosfomycin and susceptibility testing are available.
- Consider switching improving patients with ESBL complicated UTI to oral fosfomycin 3 g daily after 3 to 7 days of IV therapy
- Confirm fosfomycin susceptibility where the laboratory can test it
- Use only in patients who are clinically improving with source control
- Keep intravenous therapy for unstable patients or those not responding
- Involve the antimicrobial stewardship team in local protocols
Why it matters
It offers a randomised basis for leaving the carbapenem early in one of the commonest reasons it is used.
Don't overread it
Open-label, in patients already improving; the interval allows a cure rate up to about 8 points lower.
The statistics, in plain English
Non-inferiority means fosfomycin was shown not to be worse than IV therapy by more than a prespecified margin. The interval from −7.8 to +2.9 points includes no difference, but also a modestly lower cure rate.
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