There is an urgent need for new therapeutic approaches to counter the emergence of primary and secondary resistance to therapies that are used for treating patients with HER2+ breast cancer. With support from NCI, Lynntech is developing a novel class of HER3 antagonists that potentiate anti-tumor effects of current HER2-directed therapies via blocking ligand-dependent and ligand-independent HER3 heterodimerization. By inhibiting HER3 activity, which is one of the major modulators of resistance to HER2-directed therapies, Lynntech’s therapeutic can potentially reduce treatment failures, and improve clinical outcome of…