Fosfomycin Trometamol Compared With an Alternative Active Antibiotic as Step-down Therapy for the Treatment of Acute Pyelonephritis Due to Escherichia Coli in Elderly Women : a Randomized, Multicenter, Non-inferiority Trial - NCT07928063

Sponsor: Assistance Publique - Hôpitaux de Paris Conditions: Escherichia Coli Infection, Elderly Women, Antibiotherapy, Pyelonephritis Acute pyelonephritis (APN) is among the most common bacterial infections in older women. Oral step-down antibiotic therapy may potentially be associated with toxicity, particularly with fluoroquinolones or trimethoprim-sulfamethoxazole, espcially in geriatric patients. The emergence of resistant strains reduces the choice of oral step-down treatment, thereby increasing the risk of nosocomial complications related to intravenous access and prolonged hospitalization. Fosfomycin trometamol (FT) has broad activity against Enterobacterales, including resistant strains. It has an excellent safety profile and moderate ecological impact, and has been used for several years to treat cystitis. Recent studies have demonstrated its efficacy as an oral step-down therapy for the treatment of E.coli APN in younger women. Its efficacy in a geriatric population remains to be demonstrated. The primary objective is to demonstrate the non-inferiority, in terms of clinical cure, of FT compared with an alternative active antibiotic as step-down therapy for E. coli APN in older women. FOSFOLD is a national, multicenter, randomised, comparative, phase 3, non-inferiority trial (1:1), open-label with two parallel treatment groups. After 3 or 4 days of appropriate empirical antibiotic therapy, women aged 75 or over with E.coli APN will be randomised to receive either 3g of FT once daily or an alternative antibiotic treatment in accordance with current french guidelines, for a total of 10 days. The primary endpoint is clinical cure at Day 17, i.e. 10 days after completion of antibiotic therapy. If non-inferiority of FT is confirmed, it could provide a new therapeutic approach for oral step-down therapy in the older patients with APN. Its favorable tolerability profile could help prevent common geriatric complications, such as delirium, falls and malnutrition. Ultimately, it could help prevent some of the iatrogenic functional decline associated with hospitalisation.