Inclusion Criteria:  Capable of giving written informed consent, which includes compliance with the requirements and restrictions listed in the informed consent form (ICF) and the protocol. Patient who has newly diagnosed or historic LG NMIBC (Ta) histologically confirmed by cold cup biopsy at Screening or within 8 weeks before Screening.  Has IR disease, defined as having 1 or 2 of the following:  presence of multiple tumors. solitary tumor > 3 cm. recurrence (≥ 1 occurrence of LG NMIBC within 1 year of the current diagnosis at the initial Screening Visit). Negative voiding cytology for high-grade (HG) disease within 6 weeks before Screening.  Has adequate organ and bone marrow function as determined by routine laboratory tests as below:  Leukocytes ≥ 3,000/μL (≥ 3×10^9/L). Absolute neutrophil count ≥ 1,500/μL (≥ 1.5×10^9/L). Platelets ≥ 100,000/μL (≥ 100×10^9/L). Hemoglobin ≥ 9.0 g/dL. Total bilirubin ≤ 1.5 × upper limit of normal (ULN). Aspartate aminotransferase (AST)/Alanine aminotransferase (ALT) ≤ 2.5 × ULN. Alkaline phosphatase (ALP) ≤ 2.5 × ULN. Estimated glomerular filtration rate (eGFR) ≥ 30 mL/min. Has no evidence of active urinary tract infection (UTI) at the Screening and baseline visits. Patient is willing to receive instillations of UGN-102 at home (ie, Treatment Visits 2 to 6) by an appropriately trained home health professional. Contraceptive use by men and women should be consistent with local regulations regarding the methods of contraception for clinical study participants. Women of childbearing potential (defined as premenopausal women who have not been sterilized), including female patients and female partners of male patients, must be willing to use 2 acceptable forms of effective contraception from first instillation through 6 months post treatment. Acceptable methods of birth control that are considered to have a low failure rate (ie, less than 1% per year) when used consistently and correctly include implants, injections, combined (estrogen/progesterone) oral contraceptives, intrauterine devices (only hormonal), condoms with spermicide, sexual abstinence, or vasectomized partner. Has an anticipated life expectancy of at least the duration of the trial.  Exclusion Criteria:  Received Bacillus Calmette-Guérin (BCG) treatment for urothelial carcinoma (UC) within previous 1 year. History of HG bladder cancer (papillary or carcinoma in situ) in the past 2 years. Known allergy or sensitivity to mitomycin that in the Investigator's opinion cannot be readily managed. Clinically significant urethral stricture that would preclude passage of a urethral catheter.  History of:  neurogenic bladder. active urinary retention. any other condition that would prohibit normal voiding. Past or current T1 UC, muscle invasive UC (ie, T2, T3, T4), metastatic UC, or concurrent upper tract urothelial carcinoma (UTUC). Has an underlying substance abuse or psychiatric disorder such that, in the opinion of the Investigator, the patient would be unable to comply with the protocol. History of prior treatment with an intravesical chemotherapeutic agent in the past 2 years except for a single dose of chemotherapy immediately after any previous transurethral resection of bladder tumors (TURBT). Has participated in a study with an investigational agent or device within 30 days of enrollment.