T cell engagers are engineered proteins that direct a patient’s own T cells to kill target cells that express specific proteins, or antigens, carried by the target cells. Using its proprietary Tri-specific T cell Activating Construct (TriTAC) platform, Harpoon is developing a pipeline of novel TriTACs initially focused on the treatment of solid tumors and hematologic malignancies.

Harpoon has also developed a proprietary ProTriTAC platform, which applies a prodrug concept to its TriTAC platform to create a therapeutic T cell engager that remains inactive until it reaches the tumor. Harpoon’s third proprietary technology platform, extended release TriTAC-XR, is designed to mitigate cytokine release syndrome.

In Janaury 2024, US pharma giant Merck & Co (NYSE: MRK) entered into a definitive agreement under which Merck, through a subsidiary, to acquire Harpoon Therapeutics for $23.00 per share.