BioNTech says a breast-cancer trial met a modest PFS goal

On Oct. 26, 2026 BioNTech and DualityBio said the DYNASTY-Breast02 Phase 3 trial met its primary endpoint, a statistically significant but modest improvement in progression-free survival for trastuzumab pamirtecan, also called BNT323/DB-1303, versus investigator's choice of chemotherapy. The 541-patient study enrolled people with HR-positive, HER2-low metastatic breast cancer who had not yet received chemotherapy and whose disease had progressed on endocrine therapy; overall survival was not mature, and no survival duration or hazard ratio was published. The companies reported more interstitial lung disease than in earlier trials of the same drug, mostly Grade 1 or 2, including a small share of severe or fatal Grade 3 to 5 events, and said the likely benefit for patients is limited.