First Astellus/ AstraZeneca (AZN.US) blockbuster ADC receives FDA priority review

On October 2, Daiichi Sankyo and AstraZeneca/AZN.US announced that the FDA has accepted and granted priority review to the supplemental Biologics License Application (sBLA) for Enhertu (trastuzumab deruxtecan), their jointly developed antibody-drug conjugate (ADC), for the treatment of adult patients with HER2-low (IHC1+ or IHC2+/ISH-) or HER2-low (IHC0) expressing breast cancer who have received at least one prior line of metastatic endocrine therapy. The FDA expects to complete its review in the first quarter of 2025.

If approved, Enhertu would become the first HER2-targeted ADC to be used prior to chemotherapy in patients with metastatic breast cancer.

Breast cancer is one of the most common cancers and a leading cause of cancer-related deaths worldwide. HER2 is a tyrosine kinase receptor growth-promoting protein that is expressed on the surface of tumor cells in a variety of cancers, including breast cancer. It is estimated that approximately 60% to 65% of HR-positive, HER2-negative breast cancers are HER2-low expressing, and another 25% may be HER2-low expressing tumors. Currently, there are no approved targeted therapies specifically for HER2-low expressing patients.

Enhertu is an ADC therapy developed by AstraZeneca and Daiichi Sankyo. Earlier press releases stated that Enhertu is the first HER2-targeted ADC with an indication for any cancer.