ZW251 exhibited potent and target-specific cytotoxicity in a panel of HCC cells cultured either in monolayer or as 3D spheroids...A single administration of ZW251 resulted in robust tumor growth inhibition of a large panel of CDX and PDX models representing a range of GPC3-expression. Overall, these results support the potential of ZW251 as a novel therapeutic agent against GPC3-bearing cancers.