Among pancreatic cancer cell lines, BxPC3 and T3M4 cells expressed high expression of GPC1 compared to SUIT2 cells….GPC1-ADC showed potent antitumor effect toward BxPC3 and T3M4, while little activity in SUIT2 cells. In BxPC3 xenograft model, GPC1-ADC had significant and potent tumor growth inhibition in a dose dependent manner. In addition, using patient derived tumor xenograft (PDX) model with GPC1-positive pancreatic cancer, GPC1-ADC also showed significant tumor growth inhibition. In the tumor tissue, GPC1-ADC-mediated G2/M phase cell cycle arrest was detected in GPC1-ADC treated mice compared to control-ADC treated mice. In summary, our newly developed GPC1-ADC showed significant tumor growth inhibition against not only GPC1-positive pancreatic cell line but also patient derived GPC1-positive pancreatic cancer.