Prospective multicentre randomized double-blind placebo-controlled parallel group study on the efficacy and tolerability of StroVac® in patients with recurrent symptomatic uncomplicated bacterial urinary tract infections

PURPOSE: To evaluate efficacy and safety of vaccination with StroVac compared to placebo in patients with recurrent urinary tract infections (rUTI). MATERIAL AND METHODS: We performed a prospective, double-blinded, placebo-controlled study in patients with uncomplicated rUTI. Patients received three single intramuscular injections with StroVac every two weeks. Primary endpoint was the number of bacterial urinary tract infections (UTI) over 13.5 months after randomization and adjusted by the respective “baseline” value when comparing verum and placebo group. Secondary endpoints were the number of patients with non-recurrence, time to first recurrence, frequency of recurrences, and patients' self-assessment of quality of life using a validated questionnaire. RESULTS: 376 patients were randomized to both groups between January 2012 and March 2015. Mean age was 44.4 years. Patients were mainly female (98.4%). In the StroVac group (n = 188), the number of UTIs was reduced from 5.5 to 1.2, in the placebo group (n = 188) from 5.4 to 1.3 (p = 0.63). In patients with ≥ 7 UTIs prior to study inclusion, StroVac was statistically significantly superior to placebo (p = 0.048). However, in all other secondary endpoints, no statistical differences between the two groups could be seen (all p > 0.3). CONCLUSION: StroVac reduced the number of clinically relevant UTIs like in former studies but did not show statistically significant better results than the chosen placebo. Most likely, that was due to a, since confirmed, prophylactic effect of the chosen placebo itself. Therefore, placebo-controlled and double-blinded studies using a different ineffective placebo preparation are needed to determine the importance of StroVac in prophylaxis of rUTI.