Alphamab Oncology (Stock Code: 9966.HK) and CSPC Pharmaceutical Group Co., Ltd. ("CSPC") (Stock Code: 1093.HK) jointly announced that the first patient has been successfully dosed in the Phase III clinical study (Study ID: JSKN003-301) of anti-HER2 biparatopic antibody-drug conjugate (ADC) JSKN003. The study aims to compare the efficacy and safety of JSKN003 versus trastuzumab emtansine (T-DM1) for the treatment of HER2-positive advanced breast cancer.

Breast cancer is one of the most common malignant tumors among women worldwide and the most prevalent cancer in women in China. HER2-positive breast cancer is the most aggressive and highly malignant subtype. In recent years, the diagnosis and treatment of HER2-positive breast cancer has significantly improved. However, recurrent and metastatic breast cancer still has significant unmet clinical needs. JSKN003 is an anti-HER2 biparatopic ADC developed inhouse with Alphamab's proprietary Glycan-specific conjugation platform. Compared with its ADC counterparts, JSKN003 demonstrated better serum stability and stronger bystander effect, which effectively expands the therapeutic window. The Phase III clinical studies of JSKN003 for HER2 low-expressing breast cancer (JSKN003-302) and platinum-resistant ovarian cancer (JSKN003-306) are currently progressing smoothly.

JSKN003-301 is a randomized, controlled, open-label, multicenter, Phase III clinical study aimed at evaluating the efficacy and safety of JSKN003 compared to emtansine (T-DM1) in the treatment of patients with HER2-positive, unresectable locally advanced or metastatic breast cancer who have previously received trastuzumab or taxane-based therapies. The primary endpoint of the study is progression-free survival (PFS) as assessed by the Blinded Independent Review Committee (BIRC). The expedited progression of this study is anticipated to offer a treatment option with improved efficacy and safety for this patient population, further improving prognosis and quality of life.