Alphamab Oncology Receives Approval to Initiate Phase III Clinical Trial of JSKN003 for HER2-Positive Advanced Colorectal Cancer in China
Monday, October 27, 2025
On October 27, 2025, Alphamab Oncology, an innovative biopharmaceutical company based in Suzhou, China, announced that its lead investigational asset, the biparatopic HER2-targeting antibody-drug conjugate (ADC) JSKN003, has received formal approval from China’s Center for Drug Evaluation (CDE) under the National Medical Products Administration (NMPA) to commence a pivotal Phase III clinical study for HER2-positive advanced colorectal cancer (CRC). This trial marks a significant advancement for JSKN003, as it becomes the fourth late-stage clinical trial for the compound, underlining the company’s comprehensive clinical development plan in major oncological indications.
Colorectal cancer is one of the most prevalent cancers globally, and China accounts for over 500,000 new diagnoses annually. Notably, about 83% of Chinese CRC patients present at an advanced stage at diagnosis, and approximately 44% exhibit metastatic disease to organs such as the liver or lungs. Despite the availability of several systemic therapies, the prognosis for metastatic CRC remains poor, with a 5-year survival rate below 20%. There are currently no approved HER2-targeted therapies for CRC in China. The median progression-free survival (mPFS) for this patient group with standard therapies is only 2.0–3.7 months, underscoring the sizable unmet need for innovative interventions targeting the HER2 pathway.
Developed independently by Alphamab Oncology and co-developed with JMT-Bio Technology, a wholly owned subsidiary of CSPC Pharmaceutical Group, JSKN003 is a next-generation biparatopic ADC engineered for enhanced specificity and anti-tumor potency. The compound leverages proprietary site-specific conjugation technologies, binding strongly to two separate HER2 epitopes on tumor cells and internalizing to release a topoisomerase I inhibitor directly within cancerous tissue. Early clinical studies have demonstrated that JSKN003 offers improved safety, tolerability, and anti-tumor activity—crucially, showing a superior therapeutic window and lower hematological toxicity compared to first-generation ADCs. Importantly, JSKN003 received Breakthrough Therapy Designation from China’s CDE for its application in HER2-positive advanced CRC following failure of conventional chemotherapies with oxaliplatin, fluorouracil, and irinotecan.
The Phase III study (JSKN003-005) is designed as a randomized, open-label, multicenter trial directly comparing the efficacy and safety of JSKN003 against current standard-of-care regimens such as regorafenib, fruquintinib, or trifluridine tipiracil. This trial is expected to provide key confirmatory data that could potentially support regulatory filings and future commercialization in China and other markets.
JSKN003 is already under evaluation in other global pivotal studies, including those for HER2-positive and HER2-low expressing breast cancer as well as platinum-resistant ovarian cancer—demonstrating Alphamab Oncology’s ambition to rapidly expand the clinical footprint of this differentiated ADC. Furthermore, JSKN003 has been granted Orphan Drug Designation by the United States Food and Drug Administration for both gastric and gastroesophageal junction cancers, and holds two NMPA Breakthrough Therapy Designations for ovarian and colorectal cancer indications.
Alphamab Oncology retains exclusive production rights for JSKN003 in China, while its partner JMT-Bio holds exclusive development and commercialization rights on the mainland. The company’s robust proprietary platform covers single-domain and bispecific antibodies, and advanced conjugation technologies, enabling Alphamab to deliver globally competitive therapies for malignancies with high unmet clinical needs. This milestone highlights continued R&D momentum among domestic biopharma innovators and underscores China’s growing leadership in targeted oncology drug development, with wide-ranging implications for both Asian and international markets facing a rising burden of colorectal and other solid tumors.
