BioNTech SE and DualityBiologics (Suzhou) Co., Ltd. said Monday their experimental breast cancer drug trastuzumab pamirtecan met a Phase 3 trial goal, but its benefit to patients may be limited amid serious lung disease cases.
The companies described the improvement in progression-free survival, the time patients lived without their cancer worsening, as statistically significant but modest. The interim review came too early for a conclusion on overall survival. They did not disclose median progression-free survival, a hazard ratio or a p-value.
The partners said interstitial lung disease occurred more often than in earlier studies of the drug. Most cases were Grade 1 or 2. Severe and fatal events, at Grades 3 through 5, occurred in a small proportion of patients. The companies gave no case counts or rates and reported no other unexpected safety problems.
The DYNASTY-Breast02 trial randomized 541 patients 1:1 to trastuzumab pamirtecan or a chemotherapy chosen by the investigator: capecitabine, paclitaxel or nab-paclitaxel. Participants had hormone receptor-positive, HER2-low metastatic breast cancer that had progressed after endocrine therapy. They had not received chemotherapy for metastatic disease. An independent central review assessed the trial’s primary measure, progression-free survival.
BioNTech’s trial listing identifies DualityBio Inc. as the study sponsor and BioNTech SE as a collaborator.
In August, BioNTech said the partners planned to submit a U.S. biologics license application in 2026 and would use breast and endometrial cancer data to guide their regulatory path. Monday’s announcement gave no updated filing timetable. The partners said they would review the findings and decide what to do next, without setting a date.
