Safety and Efficacy Study of Pembrolizumab (MK-3475) as Monotherapy in the Adjuvant Treatment of Renal Cell Carcinoma Post Nephrectomy (MK-3475-564/KEYNOTE-564)

Participants will be assigned to receive study treatment until disease recurrence, unacceptable adverse events (AEs), intercurrent illness that prevents further administration of treatment, Investigator's decision to withdraw the participant, noncompliance with study treatment or procedural requirements, administrative reasons requiring cessation of treatment, or until the participant has received 17 cycles of study treatment (approximately 1 year). Each cycle is 3 weeks long.

With Protocol Amendment 02 (dated 04 Sep 2019), the secondary study objectives for the evaluation of pharmacokinetic (PK) parameters and the presence of pembrolizumab antidrug antibodies (ADA) were reclassified as tertiary study objectives.

Inclusion criteria

• Has histologically confirmed diagnosis of renal cell carcinoma (RCC) with clear cell component with or without sarcomatoid features
• Female participants of childbearing potential must be willing to use an adequate method of contraception, for the course of the study through 120 days after the last dose of study treatment
• Male participants of childbearing potential must agree to use an adequate method of contraception, starting with the first dose of study treatment through 120 days after the last dose of study treatment
• Has intermediate-high risk, high risk, or M1 no evidence of disease (NED) RCC as defined by the following pathological tumor-node-metastasis and Fuhrman grading status:

• Intermediate-high risk RCC: pT2, Grade 4 or sarcomatoid, N0, M0; pT3, Any Grade, N0, M0
• High risk RCC: pT4, Any Grade N0, M0; pT Any stage, Any Grade, N+, M0
• M1 NED RCC participants who present not only with the primary kidney tumor but also solid, isolated, soft tissue metastases that can be completely resected at one of the following: the time of nephrectomy (synchronous) or, ≤1 year from nephrectomy (metachronous)
• Has received no prior systemic therapy for advanced RCC
• Has undergone a partial nephroprotective or radical complete nephrectomy (and complete resection of solid, isolated, soft tissue metastatic lesion(s) in M1 NED participants) with negative surgical margins
• Must have undergone a nephrectomy and/or metastasectomy ≥28 days prior to signing informed consent and ≤12 weeks prior to randomization
• Must be tumor-free as assessed by the Investigator and validated by either computed tomography (CT) or magnetic resonance imaging (MRI) scan of the brain and chest, abdomen, and pelvis and a bone scan ≤28 days from randomization
• Must have provided adequate tissue per the following: Nephrectomy only: tissue from nephrectomy (required); Synchronous M1 NED: tissue from nephrectomy (required) AND, metastasectomy tissue (if available); Metachronous M1 NED: tissue from metastasectomy (required) AND, nephrectomy tissue (if available)
• Has an Eastern Cooperative Oncology Group Performance Status (ECOG PS) score of 0 or 1
• Has adequate organ function

Exclusion criteria

• Has had major surgery, other than nephrectomy and/or resection of pre-existing metastases for M1 NED participants, within 12 weeks prior to randomization
• Has received prior radiotherapy for RCC
• Has pre-existing brain or bone metastatic lesions
• Has residual thrombus post nephrectomy in the vena renalis or vena cava
• 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 the first dose of study treatment
• Has an active autoimmune disease that has required systemic treatment in past 2 years (i.e., with use of disease modifying agents, corticosteroids, or immunosuppressive drugs). Replacement therapy is allowed
• Has a known additional malignancy that is progressing or required active treatment ≤3 years ago. Exceptions include early-stage cancers (carcinoma in situ or Stage 1) treated with curative intent, basal cell carcinoma of the skin, squamous cell carcinoma of the skin, in situ cervical cancer, in situ prostate cancer, or in situ breast cancer that has undergone potentially curative therapy
• Has a history of (non-infectious) pneumonitis that required steroids or has current pneumonitis
• Has an active infection requiring systemic therapy
• Has a history of, or is currently on, dialysis
• Has a known history of human immunodeficiency virus (HIV) infection
• Has known active hepatitis B or hepatitis C virus infection
• Has a known history of active tuberculosis (Bacillus tuberculosis)
• Has had a prior solid organ transplant
• Has severe hypersensitivity (≥ Grade 3) to pembrolizumab and/or any of its excipients
• Is pregnant or breastfeeding, or expecting to conceive or father children within the projected duration of the study, starting with the Screening visit through 120 days after the last dose of study treatment
• Has received prior therapy with an anti-programmed cell death protein 1 (anti-PD-1), anti-programmed cell death-ligand 1 (anti-PD-L1), or anti-programmed cell death-ligand 2 (anti-PD-L2) agent or with an agent directed to another co-inhibitory T-cell receptor (i.e., cytotoxic T-lymphocyte-associated protein 4 [CTLA-4], OX-40, CD137 [tumor necrosis factor receptor superfamily member 9 (TNFRSF9)]) or has previously participated in a Merck pembrolizumab (MK-3475) clinical trial
• Has received prior anticancer therapy, monoclonal antibody, chemotherapy, or an investigational agent or device within 4 weeks or 5 half-lives (whichever is longer) before first dose of study treatment or not recovered (i.e., must be ≤ Grade 1 or at Baseline) from AEs due to previously administered agents
• Has received a live vaccine within 30 days prior to the first dose 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 prior to the first dose of study treatment