ALPHAMAB-B (09966) announced that the new drug application (NDA) for KN026 in combination with chemotherapy for treating patients with human epidermal growth factor receptor 2 (HER2) positive (HER2+) locally advanced, recurrent, or metastatic gastric/gastroesophageal junction (GC/GEJ) adenocarcinoma who have failed at least one prior systemic therapy (which must include trastuzumab combined with chemotherapy) has been accepted by China's National Medical Products Administration (NMPA).

The drug was developed in collaboration with Shanghai Jinmante Biotechnology Co., Ltd., a subsidiary of CSPC PHARMA (01093). The NDA submission is primarily based on a pivotal Phase II/III clinical trial, whose interim analysis results demonstrated that KN026 combined with chemotherapy significantly improved clinical efficacy compared to existing standard treatments, extending patients' progression-free survival (PFS) and overall survival (OS). The treatment showed no new safety risks, with low incidence of cardiac toxicity and low immunogenicity.

Additionally, KN026 received breakthrough therapy designation from the NMPA's Center for Drug Evaluation on November 4, 2023, and was granted priority review status on August 28, 2025. Currently, there are no approved anti-HER2 drugs for second-line treatment of HER2+ gastric cancer. KN026 represents the first anti-HER2 bispecific antibody drug in China to achieve positive results in second-line gastric cancer treatment.

The Phase II clinical trial results for KN026 were first presented at the 2024 European Society for Medical Oncology Annual Meeting, showing an objective response rate of 40.0% for KN026 combined with chemotherapy, with a median PFS of 8.6 months as assessed by an independent review committee.