BioNTech’s HER2 antibody-drug conjugate has beaten Roche’s Kadcyla in a phase 3 breast cancer trial, positioning the company’s partner Duality Biologics to seek approval for the candidate in China.
Trastuzumab pamirtecan, also known as BNT323 and DB-1303, uses the same HER2 antibody as Kadcyla and AstraZeneca and Daiichi Sankyo’s Enhertu. The rival ADCs are already approved. Yet, BioNTech and DualityBio have identified opportunities to claim a piece of the market by pairing the established targeting antibody with a different linker technology and cytotoxic payload.
DualityBio pitted its ADC against Kadcyla in a phase 3 trial in China. Investigators randomized 228 people to receive the investigational or approved ADC. Patients had previously received chemotherapy and the anti-HER2 antibody trastuzumab, which Roche sold as Herceptin and is now also used for ADC targeting.
At a pre-specified analysis, the study met its primary progression-free survival endpoint. BioNTech and DualityBio are yet to share the numbers behind the primary endpoint hit or any other results from the trial. The findings were, however, apparently encouraging enough for DualityBio to outline plans to talk to regulators about seeking approval in China, where it retains rights to the ADC under the terms of its deal with BioNTech.
Victory over Kadcyla, which won FDA approval in 2013, is table stakes for competing in the HER2 ADC market. AstraZeneca and Daiichi linked Enhertu to a 22-month improvement in PFS compared to Kadcyla in 2022. The global study enrolled a similar patient population to DualityBio’s Chinese trial.
Data from the DualityBio trial and upcoming readouts from global studies in HER2-low breast cancer and endometrial cancer will provide a clearer picture of how BNT323 compares to Enhertu. The potential of combinations with BNT327, BioNTech’s PD-L1xVEGF-A bispecific, means there is scope for the ADC to be a useful asset for the German biotech even if it is unable to unseat Enhertu.