Phase I Study of Inactivated UPEC-FimON for Non Muscle Invasive Bladder Cancer After BCG or Intravesical Chemotherapy Failure

This is a Phase I, open-label, multicenter, dose-escalation study that aims to evaluate the safety and tolerability of intravesical inactivated Instillations of UPEC-FimON (Uro-Pathogenic E. coli) in participants with non-muscle invasive urothelial carcinoma (NMIUC) of the urinary bladder who failed previous Bacillus Calmette-Guérin (BCG) or intravesical chemotherapy. Up to 30 participants will be enrolled, with 3 participants per cohort, following a dose-escalation model, with the potential for dose expansion. Dose-escalation and dose modification decisions will be based on an assessment of dose-limiting toxicities (DLTs), overall safety, and tolerability, and will be agreed upon by the Data Safety Monitoring Board (DSMB).

Inclusion Criteria: * Male or female participants aged 18 years or older at the time of consent. * Participants who were diagnosed with non-muscle invasive urothelial carcinoma (NMIUC). * Participants who underwent complete transurethral excision of recurrent intermediate- to high-risk NMIUC; have no evidence of recurrent disease at screening cystoscopy and urine cytology (residual carcinoma in situ \[CIS\] is acceptable); and have a history of at least one course of adjuvant intravesical immunotherapy or chemotherapy within 2 years before recurrence, i.e., BCG- or intravesical chemotherapy-failure NMIUC. * Initial treatment scheduled within 8 weeks after the last transurethral resection of bladder tumor (TURBT). * Women of childbearing potential must use a highly effective contraceptive method and have a negative serum beta-human chorionic gonadotropin (β-hCG) test at screening and a negative urine pregnancy test before the first study-drug administration. * Male participants agree to use a condom for 1 week post each treatment. Exclusion Criteria: * Pregnant or breast-feeding women, or women who plan to breastfeed during the study. * Concomitant upper tract urothelial carcinoma. * Muscle-invasive urothelial carcinoma. * Metastatic urothelial carcinoma. * Karnofsky Performance Status below 60. * Known immunodeficiency or immunodeficient status. * Active urinary tract infection. * Other active malignancies, except for basal cell carcinoma (BCC). * Any unresolved toxicities from prior therapy greater than NCI CTCAE Version 5.0 Grade 1 at the time of starting study treatment. * Active, uncontrolled systemic bacterial, viral, fungal, or parasitic infection. * Any other medical or psychiatric condition that, in the opinion of the Investigator, could jeopardize or compromise the participant's ability to participate in the study. * Use of immunomodulating and/or immunosuppressive drugs in the past 6 months, and prophylactic use of nutritional supplements for the prevention of urinary tract infection from screening through the Week 14 visit.