APVO603 is a dual agonist bispecific antibody employing a novel mechanism of action to simultaneously target 4-1BB (CD137) and OX40 (CD134), both members of the TNF-receptor family. Dual targeting of 4-1BB and OX40 provides synergistic co-stimulation of T cells with the potential to amplify the cytotoxic function of activated T cells and NK cells, potentially leading to more robust anti-tumor responses.

The potential advantages of APVO603 include:

  • Broad Utility: Unlike chimeric antigen receptor T-cell therapies (CAR-T) and bispecific CD3-based T-cell engagers, APVO603 does not target a specific tumor antigen, thus allowing for broad potential therapeutic use for a number of different types of solid tumors.
  • Reduced Toxicity: Since 4-1BB and OX40 are costimulatory receptors that are primarily expressed only on a limited number of T cells that have previously been exposed to tumor antigen, we believe APVO603 has the potential to cause less toxicity compared to traditional CD3-based T-cell engagers due to its selectivity.
  • Differentiation from 4-1BB Agonistic Monoclonal Antibodies: Because APVO603 contains an Fc that does not interact with Fc gamma receptors, it has the potential to be less toxic than monospecific 4-1BB antibodies.
  • Synergistic Activity: While the activation of either 4-1BB or OX40 alone stimulates anti-tumor T-cell responses, as a dual agonist bispecific antibody APVO603 has the potential to produce a synergistic or amplified response resulting in more robust T-cell responses.