This study will consist of two parts.~Part 1 - Dose regimen selection: An open-label, 30 patient, 3-arm PK assessment of: Arm 4 (previously 1): LBP-EC01 (approximately 2×10^12 PFU) given by IU administration on D1 and D2 and LBP-EC01 (approximately 1×10^11 PFU) IV given as a 1 milliliter (mL) bolus QD from D1 through D3 concomitantly with oral trimethoprim/sulfamethoxazole (TMP 160mg/SMX 800mg) BID from D1 through D3 (6 doses); Arm 5 (previously 2): LBP-EC01 (approximately 2×10^12 PFU) given by IU administration on D1 and D2 and LBP-EC01 (approximately 1×10^10 PFU) IV given as a 1 mL bolus QD from D1 through D3 concomitantly with oral TMP/SMX BID from D1 through D3 (6 doses); Arm 6 (previously 3): LBP-EC01 (2×10^12 PFU) given by IU administration on D1 and D2 and LBP-EC01 (approximately 1×10^12 PFU) IV given as a 100 mL IV infusion over 2 h on D1 through D3 concomitantly with oral TMP/SMX BID from D1 through D3 (6 doses).~Part 2 - Efficacy, Safety, Tolerability and Pharmacokinetics: A blinded, 550 patient, 1:1 randomized evaluation of the dose regimen selected from Part 1 versus placebo + antibiotic (TMP/SMX -160 mg TMP and 800 mg SMX) given orally BID on Days 1 through 3.
This is a Phase 2/3 superiority study of LBP-EC01, a recombinant bacteriophage cocktail, with an initial 3-arm pharmacokinetic (PK) lead-in portion of 30 patients to evaluate the optimal dosing regimen to be used in the subsequent 550 patient portion of the study which will be randomized 1:1 comparing LBP-EC01 + antibiotic versus placebo + antibiotic in patients with a history of prior urinary tract infection (UTI) cased by E. coli. All patients will be required to have an active acute uncomplicated UTI at baseline.