HP3 + HP3.1 + ES19 (Unity Health Toronto)

HP3 + HP3.1 + ES19 is a biologic, combination therapy consisting of three bacteriophages (HP3, HP3.1, and ES19) being evaluated for the treatment of drug-resistant urinary tract infections. [2, 3] Developed at Unity Health Toronto, this experimental phage cocktail targets Escherichia coli, including multidrug-resistant and ESBL-producing strains that cause recurrent UTIs. [2] The mechanism of action involves the phages infecting and lysing the bacterial cells, thereby reducing the bacterial load and associated biofilm. [6] The therapy has been studied in single-patient Phase I/II clinical trials where it was administered orally, topically, and via bladder instillation. [2, 3] The individual phages have been characterized and are devoid of toxins, antibiotic resistance genes, and integrase genes, making them suitable for therapeutic applications. [4]