SUZHOU, China, December 20, 2025 /PRNewswire/ — Alphamab Oncology (stock code: 9966.HK) announced that the HER2-targeting biparatopic antibody-drug conjugate (ADC) JSKN003, independently developed by the Company and co-developed with JMT-Bio Technology Co., Ltd., a wholly owned subsidiary of CSPC Pharmaceutical Group Co., Ltd. (stock code: 1093.HK), was granted a Breakthrough Therapy Designation (BTD) by the U.S. Food and Drug Administration (FDA) for the treatment of adult patients with platinum-resistant advanced or metastatic recurrent epithelial ovarian cancer, HER2-expressing primary peritoneal or fallopian tube cancer (PROC) (IHC 1+, 2+, and 3+) who have received prior treatment with bevacizumab.
Previously, JSKN003 received FDA approval to initiate a Phase II clinical study for the treatment of PROC not limited by HER2 expression, obtained FDA Fast Track Designation (FTD) for PROC, and received FDA Orphan Drug Designation (ODD) for gastric cancer and gastroesophageal junction (GC/GEJ) cancer. It also obtained BTDs from the Drug Evaluation Center (CDE) of the National Medical Products Administration of China (NMPA) for PROC and colorectal cancer (CRC). The granting of this BTD once again demonstrates the recognition by the international regulatory community of the clinical potential of JSKN003 and its importance as a new therapeutic candidate. The phase III clinical trial of JSKN003 for the treatment of PROC in China is currently progressing smoothly.
The granting of the BTD for JSKN003 is based on the pooled analysis of the Phase I clinical study in Australia (JSKN003-101, NCT05494918) and the Phase I/II clinical study in China (JSKN003-102, NCT05744427). Relevant data on the effectiveness and safety of PROC were released at the 2025 American Society of Clinical Oncology (ASCO) Annual Meeting.
Ovarian cancer (OC) is one of the most common malignancies of the female reproductive system. Most patients are diagnosed at an advanced stage and the disease is characterized by a high recurrence rate and significant therapeutic challenges. Standard treatment regimens recommended by authoritative guidelines, both nationally and internationally, include surgery combined with platinum-based chemotherapy and targeted maintenance therapy. However, approximately 80% of OC cases recur and ultimately progress to PROC, leaving patients with limited effective treatment options and a poor prognosis. The US National Comprehensive Cancer Network (NCCN) has recommended nonplatinum single-agent chemotherapy with or without bevacizumab as the preferred regimen for PROC. However, these non-platinum chemotherapies demonstrate limited efficacy, with an objective response rate (ORR) of only 10-15%, median progression-free survival (mPFS) of only 3-4 months, and median overall survival (OS) of approximately 12 months, highlighting an urgent need for new treatment options. The FDA’s granting of BTD will further accelerate the clinical development and regulatory review of JSKN003 and provide new choices for PROC patients worldwide.
About JSKN003
JSKN003 is expanded by site-specific conjugation with the Fc glycans of anbenitamab, resulting in a homogeneous and stable ADC with a DAR of 4. JSKN003 binds to two HER2 epitopes on tumor cells and releases topoisomerase I inhibitors through cellular endocytosis, exerting antitumor effects.
Compared to similar ADCs, JSKN003 demonstrates better serum stability, reduced hematologic toxicity, and stronger tumor inhibition and bystander effect, resulting in a significantly wider therapeutic window.
Multiple registration studies of JSKN003 are underway, including trials in HER2-positive breast cancer (BC), platinum-resistant ovarian cancer (PROC), HER2-low BC cancer, and HER2-positive colorectal cancer (CRC).
JSKN003 received Orphan Drug Designation (ODD) by the United States Food and Drug Administration (FDA) for gastric cancer (GC) and gastroesophageal junction (GEJ) cancer, received Fast Track Designation (FTD) by the FDA for the treatment of recurrent epithelial ovarian cancer, primary peritoneal cancer or fallopian tube cancer (PROC), advanced or metastatic platinum-resistant, not limited by HER2 expression, received Breakthrough Therapy Designation (BTD) by the FDA for the treatment of patients with HER2-expressing PROC who have previously received treatment with bevacizumab. The National Medical Products Administration (NMPA) also granted it two BTDs for advanced PROC and HER2-positive CRCs that have failed prior treatment with oxaliplatin, fluorouracil, and irinotecan.
In September 2024, the Company entered into 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). JMT-Bio has obtained exclusive license and sublicense rights to develop, sell, offer for sale and commercialize JSKN003, for tumor-related indications in mainland China (excluding Hong Kong, Macau or Taiwan). Alphamab retains exclusive production rights for JSKN003.
About Alphamab Oncology
Alphamab Oncology (stock code: 9966.HK) is an innovative biopharmaceutical company focused on oncology. Leveraging proprietary platforms, including single-domain antibodies, bispecific antibodies, glycan-specific conjugations, linker payloads, dual-payload ADCs and high-concentration subcutaneous formulations, the Company has built a differentiated and globally competitive pipeline, spanning leading ADC, bispecific antibody and single-domain antibody candidates.
One product has received marketing authorization: Envafolimab (KN035, brand name: 恩维达®), the world’s first subcutaneously injected PD-(L)1 inhibitor, providing greater convenience and accessibility in cancer treatment. The NMPA has accepted the New Drug Application for KN026 (Anbenitamab Injection), a HER2 bispecific antibody, for second-line or later HER2-positive gastric cancer. Four bispecific ADC candidates have entered clinical stages, and next-generation ADC pipelines, such as dual-payload ADCs, are progressing rapidly. The company has established strategic partnerships with organizations such as CSPC, ArriVent and Glenmark, spanning both product development and technology platforms.
Our overarching mission is to make cancer manageable and curable by addressing unmet clinical needs in oncology. Alphamab Oncology is continuously dedicated to developing effective, safe and globally competitive anti-tumor drugs, bringing innovative anti-cancer therapies to China for the benefit of patients. global.
SOURCE Alphamab Oncology
