Bauer HW et al. (2005) A long-term, multicenter, double-blind study of an Escherichia coli extract (OM-89) in female patients with recurrent urinary tract infections. Eur Urol 47: 542–548

A new study confirms that the immunotherapeutic agent OM-89 reduces recurrent urinary tract infection (UTI). OM-89 is a lyophilized extract of selected Escherichia coli strains in a capsule formation, containing 6 mg of bacterial extract. Previous clinical trials lasting up to 6 months have shown that OM-89 decreases episodes of UTI in adult, pediatric, pregnant, postmenopausal or paraplegic patients compared with placebo.

Bauer and co-workers carried out a multicenter, double-blind study to investigate the long-term preventive effects of OM-89 in a large cohort of exclusively female patients. A total of 454 patients with recurrent UTI were enrolled in the study, with 232 randomized to OM-89 and 222 to placebo. The dosage regimen was 1 capsule daily during months 1–3 and 1 capsule daily for the first 10 days of months 7–9.

Multiple regression analysis showed that OM-89 significantly reduced the incidence of UTI, by 34% compared with placebo, over a 12 month study period. The incidence of UTI was 43% lower compared with placebo between month 7 and the end of the study, indicating that booster courses of treatment could be beneficial. OM-89 was well tolerated and had a good safety profile.