Inclusion Criteria:

          1. Have histologically confirmed advanced or metastatic castration-resistant prostate
             cancer, bladder cancer, melanoma, non-small cell lung cancer, pancreatic cancer,
             colorectal cancer, gastric cancer, esophageal cancer, ovarian cancer, and head neck
             squamous cell carcinoma.

             Or,

             Have histologically confirmed metastatic pancreatic adenocarcinoma. Recurrent
             unresectable pancreatic cancer is acceptable as long as the treatment is first-line.

          2. Have not received any approved chemotherapy, except in the adjuvant setting.

        Exclusion Criteria:

          1. Subject was using immunosuppressive medications within 14 days before Screening with
             the exception of topical (intranasal, inhaled, and local injection), systemic
             (prednisone equivalent 10 mg/day or less), or as needed for hypersensitivity reactions
             such as computed tomography (CT) scan premedication.

          2. Subject has active infections or other serious underlying significant medical illness,
             abnormal and clinically significant laboratory findings or psychiatric illness/social
             situation.

          3. Subject is using a pacemaker, implantable cardiac defibrillator, neurostimulator,
             cochlear implants, cochlear implants, or other electronic medical equipment.

          4. Subject has documented immunodeficiency or organ transplant.

          5. Subject has an untreated central nervous system disease, leptomeningeal disease or
             cord compression.

          6. Subject has a history, or presence, of significant cardiovascular diseases; including
             uncontrolled hypertension, clinically relevant cardiac arrhythmia, unstable angina or
             myocardial infarction within 6 months before randomization, congestive heart failure >
             New York Heart Association Class II, severe peripheral vascular disease, corrected QT
             (QTc) prolongation >470 msec, clinically significant pericardial effusion.

          7. Subject has a history or presence of documented inflammatory bowel disease.

          8. Subject is known to be positive for human immunodeficiency virus infection.

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