By Fineline Cube 
Alphamab Oncology (HKG: 9966), a China-based biotechnology company, announced on October 27, 2025, that its self-developed biparatopic HER2-targeting Antibody-Drug Conjugate (ADC), JSKN003, has received approval from China’s National Medical Products Administration (NMPA) to proceed with a Phase III clinical study (Study No.: JSKN003-005) for the treatment of HER2-positive advanced colorectal cancer (CRC). This approval marks the fourth Phase III clinical trial for JSKN003, following earlier trials for HER2-low expressing breast cancer, platinum-resistant ovarian cancer, and HER2-positive breast cancer.
Drug Mechanism and Advantages
JSKN003 is a homogeneous and stable ADC with a Drug-to-Antibody Ratio (DAR) of 4, achieved through site-specific conjugation to the Fc glycans of anbenitamab. It binds to two HER2 epitopes on tumor cells and exerts its anti-tumor effect by enhancing cellular endocytosis to release a topoisomerase I inhibitor. Compared to similar ADCs, JSKN003 demonstrates superior serum stability, lower hematological toxicity, stronger tumor inhibition, and a pronounced bystander killing effect, significantly expanding its therapeutic window.
Collaboration Details
In September 2024, Alphamab Oncology entered into a licensing agreement with JMT-Bio, a wholly-owned subsidiary of CSPC Pharmaceutical Group (1093.HK). Under the agreement, JMT-Bio obtained exclusive development, sales, and commercialization rights for JSKN003 for oncology-related indications in Mainland China (excluding Hong Kong, Macau, and Taiwan), becoming the sole Marketing Authorization Holder (MAH) for these indications. Alphamab Oncology retains the exclusive manufacturing rights for JSKN003.-Fineline Info & Tech