Results of TOR001: An open-label single patient study using targeted bacteriophage therapy for the treatment of a chronic urinary tract infection

Chronic urinary tract infections are persistent bacterial infections with the potential to drive antibiotic resistance. Like other persistent bacterial infections, intracellular bacterial reservoirs and biofilm formation hinder the clearance of pathogens despite long courses of antibiotic therapy. New strategies for treatment of these persistent infections are needed. Here we describe the results of an open-label individual patient study using bacteriophage therapy to treat a chronic urinary tract infection in an immunocompetent 72-year-old woman without underlying urolithiasis or indwelling devices. We co-administered HP3.1, HP3, and ES19 bacteriophages with demonstrated in vitro activity via bladder instillation, orally, and as a topical formulation. The primary outcome was safety and tolerability of the treatment. Adverse events were monitored through daily symptom logs and laboratory analysis of blood samples obtained throughout the study. We found that the treatment was safe and well tolerated with no serious adverse events reported. No adverse events were deemed related to the study material. The secondary outcomes were clinical and microbiological efficacy as monitored through daily symptom logs and standard urine culture, respectively. Two weeks after initial clinical improvement, her condition relapsed and culture was consistent with previous isolates. Treatment with ertapenem following bacteriophage therapy led to sustained clinical and microbiologic cure. Exploratory analysis through whole genome sequencing of pre- and post-treatment isolates identified mutations in genes associated with adhesion and evasion that may influence virulence and promote clearance. These results inform expanded randomized clinical trials and support the growing literature that bacteriophage therapies are safe and effective.