BioNTech and DualityBio ADC meets goal with modest benefit

BioNTech and DualityBio said their antibody-drug conjugate trastuzumab pamirtecan met its main goal in a Phase 3 breast cancer trial, but the progression benefit was modest, lung inflammation rates were higher than in earlier testing, and the companies said the potential benefit to patients would be limited

Why it matters: The result is a setback for BioNTech's push into antibody-drug conjugates, licensed from DualityBio in a deal potentially worth more than $1.6 billion, in a HER2-low breast cancer market where AstraZeneca and Daiichi Sankyo's Enhertu is already deeply entrenched

Data as of BioPharma Dive report of October 26, 2026, read in full in this run, with Endpoints News reporting the same company announcement the same day. Figures are the companies' own characterisation of the trial; full data have not been published.

An antibody-drug conjugate from BioNTech and DualityBio met its main goal in a Phase 3 study in HER2-low breast cancer, delaying tumor progression, but the companies described the improvement as modest and said the findings suggest the treatment’s potential benefit to patients would be limited against the current treatment landscape. Treatment was associated with higher rates of interstitial lung disease than seen in earlier testing, severe and fatal events were observed in a small proportion of patients, and the trial had not run long enough to show a clear survival benefit.

The partners said they will discuss the data and determine next steps. Trastuzumab pamirtecan, obtained through BioNTech’s 2023 licensing deal with DualityBio, its first move into antibody-drug conjugates, is also in a late-stage study in HER2-positive endometrial cancer and an early-stage study in advanced solid tumors.

BioNTech and DualityBio ADC meets goal with modest benefit

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