A Study of BA1202 in Patients With Advanced Solid Tumors

Inclusion Criteria: * Patients who voluntarily sign an IRB-approved informed consent form, and are willing to abide by the restrictions of the study. * Part A: Patients with histologically and/or cytologically confirmed advanced and/or metastatic solid tumors who have progressed on Standard-Of-Care (SOC), are intolerant to SOC, or have no SOC. * Part B: Patients with histologically and/or cytologically confirmed colorectal cancer, non-small cell lung cancer, pancreatic cancer, gastric cancer, who have progressed on Standard-Of-Care (SOC), are intolerant to SOC, or have no SOC.（Specific cohort will be determined after data of dose escalation phase is obtained） * Part B: High expression of CEACAM5 (defined as ≥ 20% of tumor cells with IHC 2+ and/or 3+). * Life expectancy of at least 3 months. * At least one evaluable lesion in Part A and at least one measurable lesion in Part B according to RECIST v1.1. * ECOG score of \< 2. * Absolute neutrophil count ≥ 1.5 x 10\^9/L, platelet count ≥ 100 x 10\^9/L, hemoglobin ≥ 90 g/L. * Total bilirubin ≤ 1.5×ULN, ALT and AST ≤ 2.5×ULN (or ≤ 5.0×ULN for patients with liver metastases). * Serum creatinine ≤ 1.5×ULN, or creatinine clearance ≥50 mL/min. * International normalized ratio (INR) prothrombin time (PT) ≤1.5×ULN, activated partial thromboplastin time (APTT) ≤1.5×ULN. * Blood pregnancy test results were negative for female patients with fertility potential. Patients with fertility potential must agree to use a reliable method of contraception with their sexual partners during the study period and at least 6 months after the last administration. Exclusion Criteria: * Other malignancies within 5 years prior to screening (other than cured stage Ib or lower cervical cancer, non-invasive basal cell or squamous cell skin cancer). * Has a persistent or active infection that requires intravenous treatment. * History of severe cardiovascular and cerebrovascular disease. * Patients with autoimmune diseases requiring drug control or at risk of recurrence of autoimmune diseases. * Received any radiotherapy (other than palliative radiotherapy for bone metastases), chemotherapy, targeted therapy, immunotherapy, cell therapy, or other investigational anticancer agents within 4 weeks prior to first dose of BA1202, unless chemotherapy or targeted therapy is less than 4 weeks after first dose but has eluted ≥5 half-lives. * Have received any previous CEA targeting therapy, including but not limited to monoclonal antibodies, bisspecific antibodies, antibody-coupled drugs (ADCs), chimeric antigen receptor T cells (CAR-T), etc. * A history of allergy to BA1202 or any component of Obinutuzumab, or to other monoclonal antibodies. * Women are planning to become pregnant or are pregnant or breastfeeding. * Other conditions considered unsuitable for enrollment by the investigator.