AB122 Platform Study

Inclusion Criteria: * Is male or female aged ≥ 18 years at the time of informed consent; Willing and able to comply with scheduled visits and study procedures (except for Cohort E-2); * Has an Eastern Cooperative Oncology Group (ECOG) performance status (PS) of 0 or 1 before administration of study treatment; * Has adequate organ function as defined by the following criteria: • AST and ALT ≤ 3 × ULN; or if a patient with documented liver metastases, AST and ALT ≤ 5 × ULN * T-Bil of ≤ 1.5 × ULN * ANC ≥ 1500 /mm3 (ie, ≥ 1.5 × 109 /L by International System of Units \[SI\]) (excluding measurements obtained within 7 days after administration of granulocyte colony-stimulating factor \[G-CSF\]) * Platelet count ≥ 100000 /mm3 (SI: ≥ 100 × 109 /L) (excluding measurements obtained within 7 days after a transfusion of platelets) * Hemoglobin value of ≥ 9.0 g/dL excluding measurements within 4 weeks after a transfusion of packed red blood cells (RBCs) or whole blood * Has a life expectancy of at least 90 days; Cohort A-1 and A-2 * Japanese male and female; * Has a histologically or cytologically confirmed diagnosis of solid tumor; * Has disease progression after standard treatment for advanced or metastatic disease, are intolerant to the standard treatment; Cohort B-1 * Has a histologically or cytologically confirmed diagnosis of PDAC; * Has disease progression after or intolerant to one prior systemic chemotherapy for advanced or metastatic disease Cohort B-2 * Has a histologically or cytologically confirmed diagnosis of CRC. * Has been received one regimen of standard chemotherapy for advanced or metastatic disease, and was refractory or intolerant to the chemotherapy Cohort B-3 * Has a histologically or cytologically confirmed non-squamous NSCLC; * Has been received one or two regimen of standard chemotherapy for advanced or metastatic disease, and was refractory or intolerant to the standard treatment * Has been most recently received regimen including an ICI (anti PD-1 antibodies, anti PD-L1 antibodies or anti CTLA-4 antibodies) and platinum-based chemotherapy in combination or in sequence (i.e., platinum-based chemotherapy followed by checkpoint inhibitor therapy), and all of the following criteria must be met: * Received at least 2 doses at the most recent ICI therapy * Radiographic complete response or partial response based on investigator assessment with ICI therapy * Documented radiographic disease progression with above most recently received regimen Cohort C-1 * Has unresectable advanced or recurrent gastric cancer or gastroesophageal junction cancer as pathologically confirmed adenocarcinoma * Gastroesophageal junction cancer is defined as a tumor with an epicenter that is located within 2 cm proximal to and distal from the esophagogastric junction (the boundary of esophageal and gastric muscularis). * Has received 2-4 standard regimens listed below and has demonstrated disease progression according to imaging test during the most recent treatment or within 12 weeks after the final dose (The patient is eligible if the treatment is discontinued owing to SAEs, allergic reactions, or neurotoxicities.): * fluoropyrimidines and platinum * taxane or irinotecan * ramucirumab Cohort C-2 - Has histologically confirmed unresectable adenocarcinoma of the colon or rectum (all other histological types are excluded) * RAS status must have been previously determined (mutant or wild-type) based on local assessment of tumor biopsy; Wild type is defined as v-Ki-ras2 Kirsten rat sarcoma viral oncogene homolog (KRAS) (exon 2, 3 and 4) and neuroblastoma RAS viral (v-ras) oncogene homolog (NRAS) (exon 2, 3 and 4) wild type. \[Mutant is defined as at least KRAS or NRAS mutant (any exon, any mutation)\]. * Has received at least 2 prior chemotherapy regimens for the treatment of advanced CRC and had demonstrated disease progression according to imaging test during the most recent treatment or within 12 weeks after the final dose , or intolerance to their last regimen, and all of the following criteria must be met: * Prior treatment regimens must have included a fluoropyrimidine, irinotecan, oxaliplatin, an anti-VEGF monoclonal antibody * For RAS wild-type patients, an anti-EGFR monoclonal antibody must have included in addition to above Cohort D-1 * Has histologically confirmed advanced or metastatic NSCLC regardless of histologic type. * Has PD-L1 (≥ 50% tumor proportion score) in tumor tissue sample as determined at a local laboratory. Cohort D-2 * Has histologically diagnosed advanced or metastatic adenocarcinoma or squamous cell carcinoma of the esophagus. * No prior therapy for advanced or metastatic disease. * Adjuvant therapy or neo adjuvant therapy is not considered as prior therapy if there is no recurrence during or within 6 months after completion of the therapy. Cohort D-3 * Has histologically diagnosed advanced or metastatic adenocarcinoma or squamous cell carcinoma of the esophagus. * No prior therapy for advanced or metastatic disease, or refractory or intolerant to at least 1 cycle of standard first-line therapy. * Treatment discontinued due to intolerable toxicity or because the same drug cannot be re-treated before the disease progresses is considered as intolerable to the previous treatment. * Adjuvant therapy or neo adjuvant therapy is not considered as prior therapy if there is no recurrence during or within 6 months after completion of the therapy. Cohort D-4 * Has histologically or cytologically confirmed recurrent or advanced squamous head and neck cancer (oropharynx, oral mucosa, hypopharynx, larynx). • The confirmed status of the human papillomavirus (HPV) in cancers of the mid-pharynx. • Patient background such as combined positive score (CPS) and head and neck cancer treatment guidelines must be taken into account to confirm the validity of enrollment in this cohort. * No prior therapy for advanced or metastatic disea