Alphamab Oncology Announces Anti-HER2 Biparatopic ADC JSKN003 Received U.S. FDA IND Approval to Initiate a Phase II Clinical Study for Platinum-Resistant Ovarian Cancer
SUZHOU, China, July 31, 2025 /PRNewswire/ -- Alphamab Oncology (stock code: 9966.HK) announced that anti-HER2 biparatopic antibody-drug conjugate (ADC) JSKN003 has received approval from the U.S. Food and Drug Administration (FDA) to initiate a Phase II clinical study in the United States (study number: JSKN003-202) for the treatment of platinum-resistant recurrent epithelial ovarian cancer, primary peritoneal cancer, or fallopian tube cancer, not restricted to HER2 expression levels.
JSKN003 is an anti-HER2 biparatopic ADC developed inhouse which can bind HER2 on the surface of tumor cells and release topoisomerase I inhibitors (TOPIi) through cellular endocytosis, thereby exerting anti-tumor effects. Compared with its ADC counterparts, JSKN003 demonstrated significant differentiated advantages including better serum stability and stronger bystander effect, which effectively expands the therapeutic window. In multiple clinical studies at various stages in China and Australia, JSKN003 has shown promising tolerability, safety, and significant antitumor activity.
In China, three Phase III clinical studies of JSKN003 for the treatment of HER2-low expressing breast cancer (BC), platinum-resistant ovarian cancer (PROC), and HER2-positive BC are currently undergoing smoothly. In March 2025, JSKN003 was granted breakthrough therapy designation by the Center for Drug Evaluation (CDE) of the National Medical Products Administration of China (NMPA) for the treatment of PROC, not restricted to HER2 expression levels.
JSKN003-202 is a randomized, open-label, multi-center Phase II clinical study aimed at evaluating the safety and efficacy of JSKN003 in the treatment of patients with platinum-resistant recurrent epithelial ovarian cancer, primary peritoneal, or fallopian tube cancer, and determine the recommended phase III dose (RP3D). The FDA approval of this U.S. Phase II trial marks a significant milestone in Alphamab Oncology's global development strategy for its innovative pipeline, which will further strengthen the Company's competitive edge in oncology therapeutics.
About JSKN003
JSKN003 is a bispecific ADC developed based on KN026 using Alphamab's proprietary glycan-specific conjugation platform. JSKN003 can bind HER2 on the surface of tumor cells and release topoisomerase I inhibitors (TOPIi) through cellular endocytosis, thereby exerting anti-tumor effects. Compared with its ADC counterparts, JSKN003 demonstrated better serum stability and stronger bystander effect, which effectively expands the therapeutic window.
Results of multiple clinical studies at various stages of JSKN003 in China and Australia have demonstrated favorable safety profile, with promising efficacy of JSKN003 in heavily pretreated patients with advanced solid tumors, especially in patients with platinum-resistant ovarian cancer (PROC), HER2-expressing breast cancer (BC), or high HER2-expressing solid tumors. JSKN003 was granted breakthrough therapy designation by CDE for the treatment of platinum-resistant recurrent epithelial ovarian cancer, primary peritoneal cancer, or fallopian tube cancer. It has also been granted Orphan Drug Designation (ODD) by the U.S. Food and Drug Administration (FDA) for the treatment of gastric cancer and gastroesophageal junction cancer (GC/GEJ). Three Phase III clinical studies of JSKN003 for the treatment of HER2-low expressing BC, PROC, and HER2-positive BC as well as multiple exploratory Phase II clinical studies are currently undergoing smoothly.
In September 2024, the Company entered a licensing agreement with JMT-Bio Technology Co., Ltd. ("JMT-Bio"), a wholly-owned subsidiary of CSPC Pharmaceutical Group Co., Ltd. ("CSPC") (stock code: 1093.HK), pursuant to which, JMT-Bio was granted the exclusive license and sublicense rights to develop, sell, offer for sale and commercialize JSKN003, for the treatment of tumor-related indications (the "Field") in mainland China (excluding Hong Kong, Macau or Taiwan) (the "Territory") and become the sole marketing authorization holder for JSKN003 for the Field in the Territory. Alphamab retains the sole right to supply JSKN003.
About Alphamab Oncology
Alphamab Oncology is an innovative biopharmaceutical company focusing on oncology therapeutics. On December 12, 2019, the Company was successfully listed on the Main Board of the Hong Kong Stock Exchange, trading under the stock code 9966.
By leveraging its proprietary core technology platforms including single-domain antibodies, bispecific antibodies, glycan-specific conjugation, linker-payload, dual-payload antibody conjugation, and subcutaneous high concentration formulation for biologics, the Company has established a product portfolio with differentiated innovation and global competitiveness, covering cutting-edge areas such as antibody-drug conjugates (ADCs), bispecific antibodies, and single-domain antibodies.
The Company has one product approved for marketing (Envafolimab, the world's first subcutaneously injectable PD-(L)1 inhibitor), which has made a significant breakthrough in the convenience and accessibility of cancer treatment. Additionally, the Company has multiple bispecific antibodies and bispecific ADCs in clinical stage, while rapidly advancing the preclinical pipeline prioritizing bispecific ADCs and dual-payload ADCs. Multiple strategic collaborations based on innovative products or technology platforms have been established with partners such as CSPC, ArriVent, and Glenmark.
Our overarching mission is to make cancer manageable and curable by addressing unmet clinical needs in oncology. Alphamab Oncology is continuously dedicated to the development of effective, safe, and globally competitive anti-tumor drugs, delivering China-innovated cancer therapies to benefit patients worldwide.