MT-303

MT-303 is a first-in-class, investigational mRNA-based chimeric antigen receptor (CAR) therapy delivered via lipid nanoparticles (LNPs). It is designed to target glypican-3 (GPC3), a protein highly expressed in most hepatocellular carcinomas (HCC) and minimally present in normal tissues. The therapy works by delivering mRNA encoding a GPC3-specific CAR directly into myeloid cells in vivo, enabling these immune cells to recognize and kill tumor cells while also supporting the establishment of a cytokine-mediated immune response. Unlike traditional autologous cell therapies, MT-303 can be administered intravenously as an off-the-shelf product without preconditioning. Preclinical studies have shown strong expression of the CAR in myeloid cells and favorable safety profiles in animal models. MT-303 is currently being evaluated in a phase 1 clinical trial for advanced or metastatic HCC that overexpresses GPC3[1][2][3][4][5].