783TiP Phase I study of HFB301001, a novel OX40 agonist monoclonal antibody, in patients with solid tumors selected via Drug Intelligence Science (DIS) [Abstract]

OX40 agonist antibodies have shown promising preclinical activity but limited clinical success thus far, likely owing to a suboptimal pharmacological profile, inappropriate dosing regimen, and lack of a biomarker strategy for patient selection. HFB301001 is a novel human IgG1 agonist antibody that binds to a unique epitope on OX40 allowing for agonistic activity without competing with the endogenous OX40 ligand, inducing minimal OX40 downregulation upon co-stimulation of T cells. Also, HFB301001 can both enhance effector T cells and deplete regulatory T cells. It demonstrated more potent in vivo anti-tumor activity than a benchmark OX40 agonist, suggesting potentially superior patient benefit compared to first generation OX40 antibodies.