Overview

This study is designed to assess the antitumor efficacy and safety of pembrolizumab in combination with chemoradiotherapy (CRT) versus CRT alone in participants with muscle-invasive bladder cancer (MIBC). The primary hypothesis is that pembrolizumab + chemoradiotherapy is superior to placebo + chemoradiotherapy with respect to bladder intact event-free survival.

Eligibility

Inclusion Criteria:

• Has a histologically confirmed diagnosis of MIBC with predominant urothelial histology
• Has clinically non-metastatic bladder cancer (N0M0)
• Has planned and is eligible to receive chemoradiotherapy (CRT) and one of the protocol-specified radiosensitizing chemotherapy regimens
• Has Eastern Cooperative Oncology Group (ECOG) performance status of 0, 1, or 2
• Demonstrates adequate organ function
• Male participants are eligible to participate if they agree to the following during the intervention period and for at least 180 days after the last dose of study intervention
• Refrain from donating sperm
• Be abstinent from heterosexual intercourse as their preferred and usual lifestyle (abstinent on a long term and persistent basis) and agree to remain abstinent; or must agree to use contraception unless confirmed to be azoospermic
• A female participant is eligible to participate if she is not pregnant or breastfeeding, and at least one of the following conditions applies:
• Is not a woman of childbearing potential (WOCBP)
• Is a WOCBP and using a contraceptive method that is highly effective (with a failure rate of <1% per year), with low user dependency or be abstinent from heterosexual intercourse as their preferred and usual lifestyle (abstinent on a long term and persistent basis), during the intervention period and for at least 180 days after the last dose of study intervention; and agrees not to donate eggs (ova, oocytes) to others or freeze/store for her own use for the purpose of reproduction during this period

Exclusion Criteria:

• Has the presence of diffuse carcinoma in situ (CIS) (multiple foci of CIS) throughout the bladder
• Has the presence of urothelial carcinoma (UC) at any site outside of the urinary bladder in the previous 2 years except for Ta stage/T1 stage/CIS of the upper tract if the participant has undergone a complete nephroureterectomy
• Has a known additional malignancy that is progressing or has required active therapy within the past 3 years, except basal cell carcinoma of the skin, squamous cell carcinoma of the skin, superficial bladder cancer or other carcinoma in situ that has undergone potentially curative therapy
• Has the presence of bilateral hydronephrosis
• Has limited bladder function with frequency of small amounts of urine (< 30 mL), urinary incontinence, or requires self-catheterization or a permanent indwelling catheter
• Has received prior pelvic/local radiation therapy or any antineoplastic treatment for muscle-invasive bladder cancer (MIBC). Treatment for non-muscle invasive bladder cancer (NMIBC) with intravesical instillation therapy that was completed 28 days prior to randomization is allowed. Prior systemic treatment of NMIBC is not permitted.
• Received prior therapy with an anti-PD-1 (programmed cell death protein 1), anti-PD-L1 (programmed death-ligand 1), or anti-PD-L2 (programmed cell death 1 ligand 2), or with an agent directed to another stimulatory or co-inhibitory T-cell receptor (e.g., CTLA-4 [cytotoxic T-lymphocyte-associated protein 4], OX 40, or CD137 [cluster of differentiation 137])
• Has received a live vaccine within 30 days prior to the first dose of study drug
• Is currently participating in or has participated in a study of an investigational agent or has used an investigational device within 4 weeks prior to the first dose of study intervention
• Has severe hypersensitivity (Grade 3) to pembrolizumab and/or the selected chemotherapy regimen, and/or any of their excipients
• Has a diagnosis of immunodeficiency or is receiving chronic systemic steroid therapy (in dosing exceeding 10 mg daily of prednisone equivalent) or any other form of immunosuppressive therapy within 7 days prior to the first dose of study drug
• Has an active autoimmune disease that has required systemic treatment in the past 2 years (ie, with use of disease modifying agents, corticosteroids or immunosuppressive drugs). Replacement therapy (eg, thyroxine, insulin, or physiologic corticosteroid replacement therapy for adrenal or pituitary insufficiency) is not considered a form of systemic treatment and is allowed
• Has a history of non-infectious pneumonitis that required steroids or has current pneumonitis
• 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 a known history of active tuberculosis (TB; Bacillus tuberculosis)
• Has a known psychiatric or substance abuse disorder that would interfere with the participant's ability to cooperate with the requirements of the study
• Has had an allogenic tissue/solid organ transplant