Ipilimumab, a fully human IgG1 monoclonal antibody, is the only commercially available CTLA-4 antagonist. YH001 showed dose-dependent in vivo anti-cancer efficacy, as well as Treg depletion and increased CD8+/Treg ratio in human CTLA-4 knock-in mice bearing MC38 tumors.Exposure to YH001 was dose proportional with a half-life of approximately 5 days in cynomolgus monkey. Our preclinical investigation of YH001 demonstrates Biocytogen’s capability in discovering clinical candidates using its robust antibody discovery platform.