On July 2, 2025, Bio-Thera Solutions announced that its independently developed EGFR/HER3 bispecific ADC, izabren (BL-B01D1), achieved the primary endpoint in the interim analysis of its Phase III clinical trial for nasopharyngeal carcinoma (Protocol No. BL-B01D1-303). This marks the first Phase III success for BL-B01D1 and establishes it as the world’s first bispecific ADC to complete a Phase III study.
BL-B01D1 is currently being evaluated in more than 40 clinical trials across China and the United States for multiple tumor types. To date, izabren has received breakthrough therapy designation from the Center for Drug Evaluation of the National Medical Products Administration for five separate indications. For this blockbuster asset, Bristol Myers Squibb (BMS) licensed the ex-China rights to BL-B01D1 in December 2023, paying 800 million USD upfront with a total deal value of up to 8.4 billion USD, setting a new record for overseas out-licensing of a Chinese innovative drug.
Since the discovery of the HER3 target in 1989, global pharmaceutical companies have invested heavily in its development, but none succeeded in overcoming its druggability challenges. HER3 has long been known as a “black hole” for drug development. For more than three decades, no targeted therapy against HER3 has ever reached the market. The core difficulty stems from HER3 biology: low binding affinity, extremely low intrinsic kinase activity, and the absence of reliable biomarkers to guide development. These characteristics make it difficult for traditional monoclonal antibodies or small molecules to effectively modulate HER3 signaling.
With repeated failures in HER3-targeted drug development, Chinese innovators pursued a different strategy by designing bispecific ADCs simultaneously targeting EGFR and HER3. This approach delivered breakthrough progress in a field that had stagnated for decades. After BL-B01D1 was licensed to BMS, in January 2025 another EGFR/HER3 bispecific ADC, DB-1418 (AVZO-1418), developed by Innogen Bio, also secured an international licensing deal. Avenzo Therapeutics acquired the ex-Greater China rights with a 50 million USD upfront payment and 1.15 billion USD in milestones. The back-to-back landmark transactions from two Chinese companies demonstrate the global pharmaceutical industry’s strong confidence in EGFR/HER3 bispecific ADC technology platforms.
To support the development of bispecific antibody ADCs, Kyinno Biotechnology launched its common light chain mouse antibody discovery platform. This platform features strong immune responses, high sequence diversity, and robust antibody internalization. Bispecific antibodies assembled using this platform offer advantages such as simplified manufacturing, strong molecular solubility, and favorable developability. Combined with Kyinno Biotechnology’s integrated early-stage antibody drug R&D service platform and AI innovation platform, the company accelerates and strengthens project progression. Kyinno Biotechnology also holds global patent licensing for this platform, ensuring safety and freedom to operate in downstream drug development.
Selected internalization data from existing molecular assets are shown below:
Internalization results for TROP2-targeting antibodies:
Internalization results for CDH17-targeting antibodies:
Internalization results for MET-targeting antibodies:
