Definition

An antibody-drug conjugate (ADC) consisting of a human monoclonal antibody directed against the tumor-associated antigen (TAA) cluster of differentiation 70 (CD70), conjugated via a cleavable, hydrophilic linker to the camptothecin analog exatecan, with potential antineoplastic activity. Upon administration of anti-CD70 ADC PRO1160, the anti-CD70 antibody moiety targets and binds to CD70-expressing tumor cells. Upon binding, internalization and linker cleavage, exatecan is released. Exatecan inhibits DNA topoisomerase I activity, thereby inhibiting DNA replication and resulting in cell cycle arrest and tumor cell apoptosis. This inhibits the proliferation of CD70-expressing tumor cells. CD70, the ligand for the costimulatory receptor CD27 and a member of the tumor necrosis factor (TNF) family, is found on the surfaces of various types of cancer cells.