Brief Title: Perioperative Pembrolizumab (MK-3475) Plus Neoadjuvant Chemotherapy Versus Perioperative Placebo Plus Neoadjuvant Chemotherapy for Cisplatin-eligible Muscle-invasive Bladder Cancer (MIBC) (MK-3475-866/KEYNOTE-866)

PRIMARY OUTCOMES

Primary Outcome 1 - Measure: Pathologic Complete Response (pCR) Rate

Primary Outcome 1 - Timeframe: Up to approximately 15 Weeks (Time of surgery)

Primary Outcome 2 - Measure: Event-Free Survival (EFS)

Primary Outcome 2 - Timeframe: Up to approximately 72 months

CONDITION

• Urinary Bladder Cancer
• Muscle-invasive

ELIGIBILITY

Inclusion Criteria:
Have a histologically confirmed diagnosis of urothelial carcinoma (UC) / muscle invasive bladder cancer (MIBC) (T2-T4aN0M0 or T1-T4aN1M0) with predominant (≥50%) urothelial histology.

- Have clinically non-metastatic bladder cancer (N≤1 M0) determined by imaging (computed tomography (CT) or magnetic resonance imaging (MRI) of the chest/abdomen/pelvis

- Be deemed eligible for Radical Cystectomy (RC) + Pelvic Lymph Node Dissection (PLND)

- Have Eastern Cooperative Oncology Group (ECOG) Performance Status of 0 or 1

- Have adequate organ function.

- Male and female participants are eligible to participate if they agree to the contraception use as per study protocol.
Exclusion Criteria:
Has a known additional malignancy that is progressing or has required active anti-cancer treatment ≤3 years of study randomization with certain exceptions

- Has received any prior systemic treatment for MIBC or non-invasive muscle bladder cancer (NMIBC - prior treatment for NMIBC with intravesical BCG/chemotherapy is permitted) or prior therapy with an anti- programmed cell death 1 (PD-1), anti-programmed cell death ligand 1/ ligand 2 (PD-L1/L2), or anti-cytotoxic T-lymphocyte-associated protein 4 (CTLA-4)

- Has ≥N2 disease or metastatic disease (M1) as identified by imaging

- Is cisplatin-ineligible, as defined by meeting any one of the cisplatin ineligibility criteria as per protocol

- Has received prior systemic anticancer therapy including investigational agents within 3 years of randomization or any radiotherapy to the bladder

- Has undergone partial cystectomy of the bladder to remove any NMIBC or MIBC

- Has received a live or live attenuated vaccine within 30 days before the first dose of study intervention

- Has a diagnosis of immunodeficiency or has a known history of human immunodeficiency virus (HIV) infection, Hepatitis B infection or known active Hepatitis C infection

- Has a known psychiatric or substance abuse disorder

- Has had an allogenic tissue/solid organ transplant

Gender: All

Minimum Age: 18 Years

Maximum Age: N/A

Healthy Volunteers: No

OFFICIAL INFORMATION

Name: Medical Director

Role: Study Director

Affiliation: Merck Sharp & Dohme LLC

Overall Contact

Name: Medical Director

Phone: 1-888-577-8839

Email: Trialsites@merck.com

LOCATION