Efficacy and Safety of Pembrolizumab (MK-3475) in Combination With Bacillus Calmette-Guerin (BCG) in High-Risk Non-Muscle Invasive Bladder Cancer (HR NMIBC) (MK-3475-676/KEYNOTE-676)

Inclusion Criteria:

- Has histologically-confirmed diagnosis of non-muscle invasive (T1, high grade Ta
and/or CIS) transitional cell carcinoma (TCC) of the bladder

- Has been treated with one adequate course of BCG induction therapy for the treatment
of HR NMIBC

- Following adequate BCG induction therapy, must have persistent or recurrent HR NMIBC

- Has undergone cystoscopy/ transurethral resection of bladder tumor (TURBT) to remove
all resectable disease

- Has provided tissue for biomarker analysis

- Has Eastern Cooperative Oncology Group (ECOG) performance status of 0, 1, or 2

- Has adequate organ function

- Male participants must agree to use approved contraception during the treatment period
and for at least 120 days after the last dose of study treatment and refrain from
donating sperm during this period

- Female participants who are not pregnant, not breastfeeding, and either not a woman of
child bearing potential (WOCBP) or are a WOCBP who agrees to use approved
contraception during the treatment period and for at least 120 days after the last
dose of study treatment

Exclusion Criteria:

- Has persistent T1 disease following an induction course of BCG

- Has muscle invasive (i.e., T2, T3, T4), locally advanced non-resectable or metastatic
UC

- Has concurrent extra-vesical (i.e., urethra, ureter, renal pelvis) non-muscle invasive
TCC of the urothelium, concurrent upper tract involvement, or invasive prostatic TCC
including T1 or greater disease, or ductal invasion

- WOCBP who has a positive urine pregnancy test within 72 hours prior to randomization

- Has received prior therapy with anti-PD-1, anti-PD-L1, or anti-PD-L2 agent or with an
agent directed to another co-inhibitory T-cell receptor

- Has received prior systemic anti-cancer therapy including investigational agents
within 4 weeks of start of study treatment

- Is currently participating in or has participated in a study of an investigational
agent or has used an investigational device within 4 weeks of start of study treatment

- Has a diagnosis of immunodeficiency or is receiving chronic systemic steroid therapy
or any other form of immunosuppressive therapy within 7 days of start of study
treatment

- Has a known additional malignancy that is progressing or requires active treatment
within the past 3 years

- Has an active autoimmune disease that has required systemic treatment in past 2 years

- Has a history of (non-infectious) pneumonitis that required steroids or has current
pneumonitis

- Has one or more of the following contraindications to BCG: prior BCG sepsis or
systemic infection, total bladder incontinence, or an adverse experience to a previous
BCG instillation that resulted in treatment discontinuation and precludes retreating
with BCG

- Has an active infection requiring systemic therapy

- Has a known history of human immunodeficiency virus (HIV) infection

- Has a known history of Hepatitis B or known active Hepatitis C virus infection

- Has evidence of active tuberculosis

- Is pregnant or breastfeeding or expecting to conceive or father children within the
projected duration of the trial, starting with the screening visit through 120 days
after the last dose of trial treatment