A Study of TAR-200 in Combination With Cetrelimab or TAR-200 Alone Versus Intravesical Bacillus Calmette-Guérin (BCG) in Participants With BCG-naïve High-risk Non-muscle Invasive Bladder Cancer (HR-NMIBC)

Inclusion Criteria:

• Histologically confirmed initial diagnosis by local pathology (within 90 days of themost recent signed informed consent) of high grade non-muscle invasive bladdercancer (HR-NMIBC) (high-grade Ta, any T1 or carcinoma in-situ [CIS]), inparticipants who are Bacillus Calmette Guérin (BCG)-naïve

• BCG-naïve (participants who have not received prior intravesical BCG or whopreviously received but stopped BCG more than 3 years before date of randomizationare eligible)

• All visible papillary disease must be fully resected (absent) prior to date ofrandomization and documented at baseline cystoscopy. Local urine cytology atscreening must be negative or atypical (for high-grade urothelial carcinoma [HGUC])for patients with papillary only disease (without CIS)

• Eastern Cooperative Oncology Group (ECOG) performance status Grade 0, 1, or 2

• All adverse events associated with any prior surgery and/or intravesical therapymust have resolved to common terminology criteria for adverse events (CTCAE) version 5.0 Grade less than (<) 2 prior to date of randomization

• Participants must be willing to undergo all study procedures

Exclusion Criteria:

• Presence or history of histologically confirmed, muscle invasive, locally advanced,nonresectable, or metastatic urothelial carcinoma (that is, greater than and equalto [>=] T2)

• Must not have had urothelial carcinoma or histological variant at any site outsideof the urinary bladder (that is, urethra, ureter, or renal pelvis). Ta/any T1/CIS ofthe upper urinary tract (including renal pelvis and ureter) is allowable if treatedwith complete nephroureterectomy more than 24 months prior to randomization

• Presence of any bladder or urethral anatomic feature (example, urethral stricture)that, in the opinion of the investigator, may prevent the safe insertion, indwellinguse, removal of TAR-200 or administration of intravesical BCG. Participants withtumors involving the prostatic urethra in men will be excluded

• A history of clinically significant polyuria with recorded 24-hour urine volumesgreater than 4000 milliliters (mL)

• Indwelling catheters are not permitted; however, intermittent catheterization isacceptable