HX111

HX111 is an investigational antibody-based cancer immunotherapy being developed by HanX Biopharmaceuticals that targets the OX40 (TNFRSF4) costimulatory receptor on activated T cells and regulatory T cells to enhance antitumor immune responses.[1][3] Preclinical data indicate that HX111 promotes activation and proliferation of effector T cells, depletes OX40-positive regulatory T cells in the tumor microenvironment via antibody-dependent cellular cytotoxicity, and shows improved tumor regression, with particular efficacy when combined with PD‑1 checkpoint blockade.[1][3] The program encompasses both unconjugated monoclonal antibody formats and antibody‑drug conjugate derivatives designed for oncology indications, although it remains in early-stage development without disclosed clinical trial phases.[1][3]