Protein-Matched ADC or PDC Umbrella Trial in Advanced Pancreatic and Breast Cancer

This is a single-center, open-label, single-arm, umbrella clinical trial comprising dual cohorts for pancreatic cancer and breast cancer, with multiple sub-cohorts within each cohort. A Bayesian optimal two-stage design will be employed for dynamic decision-making. The study consists of a screening period, a treatment period, and a follow-up period. Two cohorts are established: the Pancreatic Cancer cohort (PC) and the Breast Cancer cohort (BC). During the screening period, all enrolled patients will provide fresh or archived tumor tissue for absolute quantification of membrane proteins via a mass spectrometry platform, generating an individualized "target expression profile" (expressed as molecules per cell). Targets will be ranked by expression level in descending order to identify the top 1-5 candidate targets.