Harpoon has created a novel antibody-based drug discovery platform called TriTAC™ (Tri-specific T cell Activating Construct), which offers an enhanced way to unleash the target cell-killing properties of a patient’s own immune system. The TriTAC™ platform was developed to address a number of limitations of existing approaches, which are primarily focused on treating blood cancers. In contrast, the TriTAC™ platform was specifically engineered to treat solid tumor malignancies – but it can also eliminate cells causing other severe diseases, like acute and chronic inflammation or infections.
TriTAC™ antibody constructs are composed of single polypeptides designed to bind with one arm to cancer cells, and with their second arm to capture and engage bypassing T cells. The activation of T cells by TriTAC™ antibodies releases a multitude of toxic factors that lead to the death of target cells. In a next step, T cells proliferate, and search for and repetitively destroy cancer cells in the entire body as long as the TriTAC™ antibody is present.
A third domain in TriTAC™ antibodies attaches to human serum albumin. This allows for more optimal drug exposure and less frequent treatment of patients. Binding to albumin, the major protein in blood serum, has been validated as an effective way to extend the serum half-life of proteins. Even though TriTAC™ antibodies have three binding domains, their overall size is only one third of that of monoclonal antibodies. This allows for faster penetration into tissues, particularly into tumor tissue with its difficult to reach areas.