PBX-004

**PBX-004** is an investigational antibody-drug conjugate (ADC) developed by Pinotbio Inc. for the treatment of integrin beta-6 (ITGB6)-expressing solid tumors. ITGB6, rarely expressed in normal cells but overexpressed in various cancers, serves as the target antigen. The ADC comprises an ITGB6-specific monoclonal antibody conjugated to a novel topoisomerase I inhibitor payload via a linker, enabling targeted delivery of the cytotoxic payload to tumor cells, internalization, and DNA damage-induced cell death. Preclinical data demonstrate potent antitumor activity in models of non-small cell lung cancer (NSCLC), head and neck squamous cell carcinoma (HNSCC), and triple-negative breast cancer (TNBC), comparable to or exceeding benchmarks like sigvotatug vedotin (SGN-B6A).[2][3][10][12]