MRG003 With Gemcitabine for Second-line Advanced PDAC

This is a Phase Ib/II clinical study aimed to evaluate the tolerability of becotatugvedotin in combination with gemcitabine, determine the clinically recommended dose for the combination regimen, and assess the efficacy and safety of becotatugvedotin combined with gemcitabine in patients with advanced second-line pancreatic ductal adenocarcinoma (PDAC). The study plans to enroll 27-30 patients, including 3-6 patients in the first stage (Phase I) and 24 patients in the second stage (Phase II). The study consists of three periods: screening period (including baseline), treatment period, and follow-up period (safety follow-up and survival follow-up). Eligible patients must have locally advanced unresectable or metastatic pancreatic cancer confirmed by histopathology. Phase I: After the screening period, patients will receive treatment with becotatugvedotin and gemcitabine. Becotatugvedotin will be administered at doses of 1.5 mg/kg or 2.0 mg/kg once every 3 weeks (Q3W) using a 3+3 dose escalation design. Gemcitabine will be given at 1000 mg/m² on days 1 and 8 of each 3-week cycle (Q3W). Treatment will continue until disease progression, dose-limiting toxicities (DLTs), withdrawal of informed consent, death, pregnancy, investigator decision to discontinue treatment, or study termination, whichever occurs first. Upon completion of Phase I, the study will proceed to Phase II. Phase II: After the screening period, patients will receive treatment with becotatugvedotin and gemcitabine. The dose of becotatugvedotin will be the recommended Phase II dose (RP2D) selected based on the results from Phase I, while gemcitabine will be administered at 1000 mg/m² on days 1 and 8 of each 3-week cycle (Q3W). Treatment will continue until disease progression, intolerable toxicity, withdrawal of informed consent, death, pregnancy, investigator decision to discontinue treatment, or study termination, whichever occurs first. Tumor imaging assessments will be performed using RECIST v1.1 e