trastuzumab-ICOSL

Trastuzumab-ICOSL is a preclinical recombinant fusion protein developed by Alpine Immune Sciences (a subsidiary of Vertex Pharmaceuticals). It is a 'variant monoclonal antibody' (V-mAb) consisting of the HER2-targeting antibody trastuzumab fused to engineered inducible co-stimulator ligand (ICOSL) variant immunoglobulin domains (vIgDs) generated through Alpine's directed evolution platform. This molecule is designed to localize to HER2-positive tumor cells and simultaneously provide costimulatory signals to T cells by acting as an agonist for both ICOS and CD28. By concentrating costimulatory activity within the tumor microenvironment, trastuzumab-ICOSL aims to enhance the activation, proliferation, and effector function of tumor-infiltrating lymphocytes, potentially overcoming immune evasion in HER2-positive cancers such as breast and gastric cancer.