An antibody-drug conjugate (ADC) composed of a monoclonal antibody directed against the tumor-associated antigen (TAA) delta-like protein 3 (DLL3) and linked to an as of yet unelucidated cytotoxic agent, with potential immunostimulating and antineoplastic activities. Upon administration, anti-DLL3 ADC ZL-1310 targets and binds to DLL3 found on DLL3-expressing tumor cells. Upon internalization, the cytotoxic agent causes cell death in DLL3-expressing tumor cells through an as of yet unknown mechanism of action. DLL3, a Notch pathway protein, is overexpressed on a variety of cancer cell types. It plays a key role in embryonic development and in tumor initiation and proliferation.