On 11 April 2026, BioNTech reported positive results for BioNTech and DualityBio’s investigational antibody drug conjugate, BNT323/DB-1303 (trastuzumab pamirtecan) in a Phase 2 cohort of patients with HER2-expressing, advanced endometrial cancer. The results are part of a global Phase 1/2a study assessing the safety and tolerability of trastuzumab pamirtecan in multiple solid tumours.
The Phase 2 cohort included 145 patients and, according to BioNTech, met its primary efficacy endpoint, with data demonstrating clinically meaningful antitumor activity across all HER2 expression levels and a manageable safety profile.
BioNTech and DualityBio intend to file a Biologics License Application (BLA) in the US in 2026, “subject to regulatory feedback from the FDA”.
A BLA has already been filed for BNT323/DB-1303 in China, with DualityBio announcing on 9 April 2026 that the BLA had been accepted for review by China’s National Medical Products Administration (NMPA) in respect of the treatment of unresectable or metastatic HER2-postiive adult breast cancer.
Trastuzumab pamirtecan is being developed by BioNTech and DualityBio and was “built from” DualityBio’s Duality Immune Toxin Antibody Conjugates (“DITAC”) platform. In addition to the Phase 1/2 trial in patients with advanced/metastatic solid tumours, the ADC is being evaluated in two global Phase 3 trials: Fern-EC-01 (HER2 expressing advanced recurrent endometrial cancer) and DYNASTY-Breast02 (metastatic breast cancer).