GT103

GT103 is a first-in-class, fully human-derived IgG3 monoclonal antibody that targets complement factor H (CFH), a protein that protects tumor cells from the alternative complement pathway. By binding to a tumor-specific epitope on CFH, GT103 inhibits its function, leading to increased deposition of C3b on tumor cells and promoting both antibody-dependent cellular phagocytosis and complement-dependent cytotoxicity. This results in direct killing of tumor cells and stimulation of an adaptive anti-tumor immune response. Developed by Grid Therapeutics and Duke University, with Merck Sharp & Dohme also involved, GT103 is being investigated primarily for the treatment of advanced non-small cell lung cancer (NSCLC) refractory to standard therapies. As of late 2024, it has reached Phase II clinical trials for NSCLC and Phase I for solid tumors.