By Fineline Cube 
China-based Alphamab Oncology (HKG: 9966) announced today that its drug candidate JSKN003 has received Orphan Drug Designation (ODD) from the U.S. Food and Drug Administration (FDA) for the treatment of gastric cancer (GC) and gastroesophageal junction cancer (GEJC). This designation underscores the potential of JSKN003 to address significant unmet medical needs in these conditions.
Drug Mechanism and Innovation
JSKN003 is an antibody-drug conjugate (ADC) targeting two distinct epitopes of human epidermal growth factor receptor 2 (HER2). The ADC leverages a glyco-site-specific conjugation technology to link a topoisomerase I inhibitor to the N-glycosylation sites of the antibody KN026, a recombinant humanized anti-HER2 bispecific antibody. This approach enhances serum stability and demonstrates superior efficacy compared to maleimide-Michael addition-conjugated ADCs. The dual-epitope targeting of HER2 results in improved internalization and bystander killing effects, driving robust anti-tumor activity in HER2-expressing tumors.
Clinical Development
In September 2024, Alphamab entered into a licensing agreement with Shanghai JMT Biotechnology Co., Ltd., a subsidiary of CSPC Pharmaceutical Group Ltd (HKG: 1093), for the development and commercialization of JSKN003 in mainland China. Currently, three Phase III clinical trials are underway in China, evaluating JSKN003 for HER2-positive breast cancer, HER2-low expression breast cancer, and platinum-resistant recurrent epithelial ovarian cancer, primary peritoneal cancer, or fallopian tube cancer.-Fineline Info & Tech