BioNTech SE and DualityBiologics (Suzhou) Co., Ltd. have announced that the DYNASTY-Breast02 global phase 3 clinical trial met its primary endpoint.
This demonstrated a statistically significant, yet modest improvement in progression-free survival (PFS) with trastuzumab pamirtecan compared to investigator’s choice of chemotherapy in chemotherapy-naïve patients with HR+/HER2-low metastatic breast cancer who have progressed on endocrine therapy. At this interim analysis for the secondary endpoint of overall survival (OS), data were not mature.
A higher rate of interstitial lung disease (ILD) was reported in this trial compared to prior trials with trastuzumab pamirtecan, with most cases being Grade 1 and 2. Severe and fatal events were reported in a small proportion of patients (Grade 3-5). Otherwise, the overall safety profile was consistent with prior clinical trials and no new safety signals were observed.
The available efficacy and safety data, as of this data cut-off date, suggest the potential benefit to patients would be limited in the context of the HR+/HER2-low metastatic breast cancer treatment landscape. The companies will discuss the data and determine next steps.
BioNTech and DualityBio are developing trastuzumab pamirtecan in three ongoing clinical trials, including two global phase 3 clinical trials, in HR+/HER2-low metastatic breast cancer and in HER2-expressing recurrent endometrial cancer, as well as in a global phase 1/2 clinical trial in patients with advanced/metastatic solid tumours.