Sino Biopharmaceutical Limited (1177) announced that it has completed subject enrollment for a Phase III clinical trial evaluating TQB2102, described as a next-generation HER2 dual-epitope bispecific antibody-drug conjugate (ADC). The trial compares TQB2102 with investigator-selected chemotherapy in HER2-low recurrent/metastatic breast cancer patients.

TQB2102 utilizes an asymmetric design targeting ECD II/IV domains of the HER2 protein, with an enzyme-cleavable linker and an optimized drug-to-antibody ratio. These features are intended to enhance tumor selectivity, increase cytotoxic payload delivery, and broaden the killing range through a bystander effect, while reducing potential side effects.

Data presented at the 2025 American Society of Clinical Oncology (ASCO) Annual Meeting indicate that TQB2102 achieved an overall objective response rate of 53.4% among heavily pretreated HER2-low patients. The 7.5mg/kg cohort achieved a 58.3% response rate, and patients previously exposed to ADCs showed a 44.4% remission rate. Grade ≥3 treatment-related adverse events mainly included neutropenia, leukopenia, anemia, and hypokalemia.

According to the announcement, approximately 45%-55% of breast cancers in China are classified as HER2-low expression, a subtype that lacks effective targeted therapies. Sino Biopharmaceutical Limited has built a pipeline aimed at multiple breast cancer subtypes, covering diverse treatment stages from neoadjuvant therapy to palliative care, with TQB2102 positioned as a potential new treatment option for HER2-low patients.