Prevention of recurrent lower urinary tract infections by long-term administration of fosfomycin trometamol. Double blind, randomized, parallel group, placebo controlled study.

Three hundred and seventeen non pregnant females, suffering of recurrent lower urinary tract infections (UTIs; at least three episodes in the preceding 12 months) were enrolled in a double blind, randomized placebo (PL) controlled, parallel group clinical study, addressed to evaluate the efficacy and safety of fosfomycin trometamol (CAS 78964-85-9, FT, Monuril) in the prevention of infectious recurrences of lower urinary tract. One hundred and sixty six and 151 patients were allocated at random to FT or to PL treatment. The assigned treatment, i.e. one sachet containing FT equivalent to 3 g. of fosfomycin or PL, was taken by patients every 10 days during 6 months; thereafter they were followed up for another 6 consecutive months. Three hundred and two evaluable patients, completed the study as per protocol, 158 in the FT and 144 in the PL group, respectively. The analysis of the number of urinary tract infections/patient-year (primary end point) showed a result of 0.14 infections/patient-year in the FT group and of 2.97 infections/patient-year in the PL group. The difference was highly significant (p < 0.001). The time to first infection recurrence was significantly longer in the FT (38 days) than in the PL group (6 days); p < 0.01. The number of patients with at least one episode of recurrent infection and the number of episodes/patient during the treatment as well as during the follow-up period were statistically significantly lower in the FT group than in the PL group. Both treatments were well tolerated; only one adverse reaction possibly treatment related, i.e. an allergic skin reaction, was reported in both groups. Haematology and blood chemistry variables explored for safety at the end of the study did not show any significant difference between the two groups. The compliance with the treatment in the 302 evaluable patients was excellent. The results of this trial indicate that FT is higly effective in the prophylaxis of UTI recurrences; this beneficial effect is evident also in the 6 months of the follow-up.