Inclusion Criteria:

          -  For Part 1 and Part 2, diagnosis of advanced/metastatic colorectal, gastric or
             esophageal adenocarcinoma that is resistant to standard therapy or for which no local
             regulatory approved standard therapy is available that would confer significant
             benefit.

          -  For Part 2, diagnosis of colorectal adenocarcinoma that is resistant to standard
             therapy or for which no standard therapy is available

          -  Eastern Cooperative Oncology Group (ECOG) Performance Status (PS) 0 or 1

          -  Measurable disease or non-measurable disease and refractory to or intolerant of
             existing therapies (Part 1)

          -  Measurable disease as defined by RECIST 1.1 is required (Part 2)

        Exclusion Criteria:

          -  Known active uncontrolled or symptomatic Central Nervous System (CNS) metastases

          -  Other active malignancy within 3 years prior to randomization, except for adequately
             treated basal cell or squamous cell skin cancer, or carcinoma in situ

          -  Major surgery or radiation within 3 weeks prior to study entry

          -  Last anti-cancer treatment within 4 weeks prior to study entry

          -  Active or history of clinically significant autoimmune disease that required systemic
             immunosuppressive medication

          -  Active or history of clinically significant gastrointestinal disease

          -  Participation in other studies involving investigational drug(s) within 2 weeks prior
             to study entry

          -  Pregnant or breastfeeding female patients