ABN501

ABN501 is a first-in-class, fully human monoclonal antibody developed by Abion that selectively targets Claudin-3 (CLDN3) with high specificity and sub-nanomolar binding affinity. It specifically binds to the extracellular loop 2 (ECL2) domain of Claudin-3, a tight junction protein frequently overexpressed in various solid tumors and linked to poor clinical outcomes. ABN501 mediates anti-tumor activity primarily through antibody-dependent cellular cytotoxicity (ADCC), effectively eliminating Claudin-3-positive cancer cells. Preclinical studies have shown efficacy in models of small cell lung cancer, breast cancer, and ovarian cancer. As of 2024, preclinical development was completed, and the candidate is being positioned for further development as a monotherapy or as a component of antibody-drug conjugates (ADCs) and bispecific antibodies. In June 2025, Abion entered into a significant licensing and co-development agreement for ABN501 and other antibodies, valued at up to $1.315 billion.

Other names

Claudin-3 monoclonal antibodyClaudin3 monoclonal antibodyClaudin 3 monoclonal antibodyCLDN3 monoclonal antibodyCLDN-3 monoclonal antibodyCLDN 3 monoclonal antibody