Study of MK-3475 (Pembrolizumab) in Patients With Microsatellite Unstable (MSI) Tumors (Cohort D)

Inclusion Criteria: * Patients with microsatellite stable tumor and a tumor mutation burden (TMB) level measured at \> 20 mutations per megabase pairs (MB) * Have measurable disease * Eastern Cooperative Oncology Group (ECOG) Performance Status of 0 to 1 * Adequate organ function as defined by study-specified laboratory tests * Must use acceptable form of birth control through the study and for 28 days after final dose of study drug * Signed informed consent form * Willing and able to comply with study procedures * Agree to have a biopsy of their cancer * Patients with colon cancer must have received at least two prior cancer therapy regimens. * Patients with other cancer types must have received at least one prior cancer therapy * Progressive disease Exclusion Criteria: * Patients with uncontrolled intercurrent illness, including but not limited to ongoing or active infection, systematic congestive heart failure, unstable angina pectoris, cardiac arrhythmia or psychiatric condition that would limit compliance with study requirements. * Patients who have had chemotherapy or biological cancer therapy within 2 weeks prior to the first dose of study drug * Patients who have had radiation within 2 weeks prior to the first dose of study drug * Patients who have undergone major surgery within 4 weeks of dosing of investigational agent * Patients who have received another investigational product or investigational device within 4 weeks prior to receiving study drug * Patients who…