Zaptuzumab (AD5-10) is a humanized monoclonal antibody targeting death receptor 5 (DR5) with high selective binding affinity. It specifically induces cancer cell death through caspase-mediated apoptosis and autophagic cell death (ACD). Zaptuzumab can activate antibody-dependent cell-mediated cytotoxicity (ADCC) and complement-dependent cytotoxicity (CDC). Additionally, it induces reactive oxygen species (ROS) production and reduces glutathione (GSH) levels. In various xenograft mouse tumor models, Zaptuzumab has demonstrated significant tumor growth inhibition and favorable safety profiles.

Zaptuzumab (AD5-10) effectively kills various cancer cell lines without affecting normal cells within a concentration range of 0.01-10000 ng/mL over 48 hours. It exhibits notable cytotoxicity against Jurkat E6-1, Jurkat, J.gamma1, Reh, A3, and MT-4 cells at concentrations between 0.00001-10000 nM over 72 hours. At 5 μg/mL for 4 hours, Zaptuzumab activates antibody-dependent cell-mediated cytotoxicity (ADCC) and complement-dependent cytotoxicity (CDC) in cancer cells. At 20 μg/mL for 0.5-1.5 hours, it transfers from the plasma membrane to cytosolic compartments in NCI-H460 cells via endocytosis. Furthermore, Zaptuzumab at 1 μg/mL over 0.5-24 hours induces apoptosis in NCI-H460 cells by downregulating phosphorylated levels of caspase-8, -9, and -3. In a concentration range of 0.1-1 µg/mL, it modulates NF-κB in a dose-dependent manner and triggers the release of inflammatory cytokines such as IL-8, TNF-α, CCL20, MIP-2, and MIP-1β. At 40 ng/mL over 0-4 hours, it induces reactive oxygen species (ROS) generation in Jurkat cells and reduces glutathione (GSH) levels. Additionally, it decreases the mitochondrial membrane potential and oxidizes cardiolipin in Jurkat cells, while downregulating levels of Bid, AIF, Endo G, procaspase-8, and PARP within 0.5-4 hours. Moreover, Zaptuzumab promotes the translocation of Endo G from the cytoplasm to the nucleus in Jurkat and HCT116 cells at 40 ng/mL over 4 hours and induces sustained activation of JNK in Jurkat cells within 0-4 hours.

Zaptuzumab (AD5-10) administered at 8 mg/kg via intravenous injection as a single dose can significantly inhibit tumor growth in xenograft mouse models of Reh, J. gamma1, and Jurkat E6-1. Additionally, Zaptuzumab given at 40-80 mg/kg via intraperitoneal injection once a week for four weeks effectively suppresses tumor growth in the NCI-H460 xenograft mouse model.