SG1906

Phase Ia study objectives: Main objectives: 1) Safety and tolerability; 2) Exploration of MTD or MAD; 3) Preliminary determination of Phase II recommended dose (RP2D). Secondary objectives: 1) Evaluate the PK characteristics of SG1906 in patients with CLDN18.2-positive locally advanced unresectable or metastatic solid tumors; 2) Evaluate PD characteristics; 3) Evaluate the immunogenicity of SG1906; 4) Preliminary evaluation of the anti-tumor efficacy of SG1906 monotherapy. Phase Ib study objectives: Main objectives: 1) Determine the RP2D of SG1906 in patients with CLDN18.2-positive locally advanced unresectable or metastatic gastric/gastroesophageal junction (G/GEJ) adenocarcinoma and pancreatic cancer (PC); 2) Safety and tolerability; 3) Evaluate the tumor response of SG1906 in patients with CLDN18.2-positive locally advanced unresectable or metastatic G/GEJ adenocarcinoma and PC. Secondary objectives: 1) Evaluate the anti-tumor efficacy of SG1906 in patients with CLDN18.2-positive locally advanced unresectable or metastatic G/GEJ adenocarcinoma and PC; 2) Evaluate the pharmacokinetic PK characteristics; 3) Evaluate the PD characteristics; 4) Evaluate the immunogenicity of SG1906. Exploratory objectives To explore potential biomarkers in tumor tissue/blood that predict the efficacy of SG1906 (including but not limited to CLDN18.2 expression).