First Patient Dosed in Phase Ⅲ Study of JSKN003 for the Treatment of Advanced HER2-Low Breast Cancer

SUZHOU, China, Dec. 4, 2023 /PRNewswire/ -- Alphamab Oncology (stock code: 9966.HK) announced the first patient has been dosed in the phase III clinical study (JSKN003-302) of anti-HER2 bispecific antibody-drug conjugate JSKN003 for treatment of advanced HER2-low breast cancer.

Breast cancer is the most common cancer among women worldwide. Breast cancer is the most common malignant tumor among Chinese women. It was estimated that there were 429,000 new cases of breast cancer in China in 2022 accounting for 19.54% of all female malignant tumor incidents. Breast cancer results in 124,000 deaths annually in China, making it the leading cause of death for women under the age of 45. HER2 low expression subtype accounting for a significant 45-55% of breast cancer patients. These patients are expected to benefit from the new ADC drug therapy.

JSKN003 is a next-generation bispecific antibody conjugate developed by Alphamab Oncology. Preliminary results from a Phase I clinical study in Australia for the treatment of advanced solid tumors have observed initial efficacy and good tolerability. As of October 26, 2023, median follow-up was 4.2 months (95%CI: 2.3 to 5.8), 20 patients (62.5%) were on treatment, PFS and DOR were immature, and ORR remained to be observed. In 30 evaluable patients, ORR was 46.7% (95% CI: 28.3% to 65.7%) and DCR was 90.0% (95% CI: 73.5% to 97.7%). The ORR in patients with low HER2 expression was 40.0% (95% CI: 12.2% to 73.8%) and 75.0% (95% CI: 19.4% to 99.4%) in patients with HER2+ BC. In terms of safety, only 2 of 32 patients (6.3%) developed grade 3 TRAE. None of the patients experienced drug-related serious adverse events. The dose escalation reached 8.4mg/kg, no dose-limiting toxic reactions occurred, and the study did not reach the maximum tolerated dose (MTD).

JSKN003-302 is a multicenter, randomized, controlled phase III clinical study in patients with unresectable locally advanced or metastatic HER2 low-expressing breast cancer. The study plans to enroll 400 subjects, who will be randomly assigned in 1:1 to receive either JSKN003 or investigator's choice of chemotherapy. The primary endpoint of the study is progression-free survival (PFS) evaluated by a blinded independent central review (BICR).

About JSKN003

JSKN003 is an anti-HER2 bispecific antibody-drug conjugate (bis-ADC), which is developed inhouse with proprietary Glycan-specific conjugation platform. JSKN003 targets HER2 and triggers internalization and release the cytotoxic drug. Compared with peers, JSKN003 demonstrated stronger bystander effect and the better serum stability. Multiple clinical studies are ongoing in Australia and China. Recently a phase III trial in Her2 low expression breast cancer has been initiated.

About Alphamab Oncology

Alphamab Oncology is a biopharmaceutical company dedicated to the discovery, development manufacturing and commercialization of world-class innovative biotherapeutics for cancer treatment. On December 12, 2019, Alphamab Oncology was listed on the Main Board of Hong Kong Stock Exchange, with the stock code:9966.

To make cancer manageable and curable Alphamab Oncology has always been guided by clinical value and patient needs, and focuses on the development of innovative, safe and affordable anti-tumor drugs to benefit patients in China and around the world.

We have created a biological macromolecule drug discovery, research and development, manufactured technology platform with independent intellectual property rights such as protein/antibody engineering, antibody screening, multi-module/multi-functional antibody modification.

With multiple inhouse proprietary technology platforms, Alphamab Oncology has established a globally competitive and differentiated pipeline which consists of tumor single domain antibody/monoclonal antibodies, multi-functional antibodies, and antibody-drug conjugates. Among them, The world's first subcutaneous PD-L1 inhibitor injection (Envafolimab) has been obtained the market approval by the Chinese National Medical Products Administration, several varieties have entered the critical clinical stage in China and the United States, 2 varieties were selected into the national special project of " New Drug Development", and 3 varieties were granted 4 orphan drug qualifications by FDA.