A Study to Evaluate the Efficacy of VVD-133214 in Combination With Pembrolizumab Compared With Pembrolizumab Alone in Participants With Advanced Cancer of the Colon or Rectum

Inclusion Criteria: * Eastern Cooperative Oncology Group (ECOG) performance-status score of 0 or 1 * Have a known microsatellite instability (MSI) and/or deficient mismatch repair (dMMR) tumor status confirmed per local standard of care (SoC), and have histologically or cytologically documented advanced (unresectable and/or metastatic) colorectal adenocarcinoma (CRC) * No prior systemic treatment for metastatic disease and not amenable to curative resection * Participants must have documented MSI and/or dMMR tumor status determined as part of the routine diagnostic workup in a certified laboratory * Availability of formaldehyde-fixed paraffin-embedded (FFPE) archival tumor tissue for submission to Sponsor/central laboratory for retrospective central testing including a copy of a redacted pathology report if available * Presence of measurable disease according to RECIST v1.1 * Adequate hematologic and end-organ function, defined using laboratory results obtained within 14 days prior to first dose of study treatment * Females of childbearing potential must have negative serum pregnancy test before starting study treatment Exclusion Criteria: * Prior systemic treatment for advanced CRC. Participants may have received prior adjuvant chemotherapy as long as disease progression occurred at least 12 months after the last dose of adjuvant treatment * Prior treatment with adjuvant immunotherapy (e.g., anti-PD-1, anti-PD-L1, anti-PD-L2 agent, or anti-CTLA-4 agent, or any other antibody or drug specifically targeting T cell co-stimulation or immune checkpoint pathways, including prior therapy with anti-tumor vaccines or other immuno-stimulatory antitumor agents, etc.) * Known active or uncontrolled central nervous system (CNS) or brain metastases (progressing or requiring anticonvulsants or corticosteroids for symptomatic control) and/or carcinomatous meningitis * Patients with active or history of autoimmune disease or immune deficiency that has required treatment in past 2 years * History of malignancy other than CRC, within 5 years prior to screening. Participants with Lynch syndrome are not excluded. * Participants requiring treatment with systemic immunosuppressive medication (such as corticosteroids) within 2 weeks prior to initiation of study treatment, or anticipation of need for systemic immunosuppressive medication during study treatment * Participants with active hepatitis B, hepatitis C or HIV * Participants with known Werner Syndrome (WRN) * Prior treatment with any WRN helicase inhibitor