The purpose of this study was to evaluate the efficacy and safety of pembrolizumab plus epacadostat compared to sunitinib or pazopanib in participants with locally advanced/metastatic renal cell carcinoma (mRCC) with a clear cell component who have not received prior systemic therapy for their mRCC.

Inclusion Criteria:

• Histologic confirmation of locally advanced or metastatic RCC with a clear-cell component with or without sarcomatoid features.
• Must not have received any prior systemic therapy for their mRCC.
• Measurable disease based on RECIST v1.1.
• Archival tumor tissue sample or newly obtained core or excisional biopsy of a tumor lesion as required.
• Karnofsky performance status ≥ 70%.
• Adequate organ function per protocol-defined criteria.

Exclusion Criteria:

• Use of protocol-defined prior/concomitant therapy.
• Currently receiving or has received an investigational treatment as part of a study of an investigational agent or has used an investigational device within 4 weeks before randomization.
• History of severe hypersensitivity reaction to study treatments or their excipients.
• Active autoimmune disease that has required systemic treatment in past 2 years.
• Known additional malignancy that has progressed or has required active treatment in the last 3 years.
• Known active central nervous system metastases and/or carcinomatous meningitis.
• History of (noninfectious) pneumonitis that required steroids or current pneumonitis.
• History or presence of an abnormal electrocardiogram that, in the investigator's opinion, is clinically meaningful.
• Significant cardiac event within 12 months before Cycle 1 Day 1.

Following the first publication, the Institution and/or Principal Investigator may publish data or results from the Study, provided, however, that the Institution and/or Principal Investigator submits the proposed publication to the Sponsor for review at least sixty (60) days prior to the date of the proposed publication. Sponsor may remove from the proposed publication any information that is considered confidential and/or proprietary other than Study data and results.