AstraZeneca plc (NASDAQ:AZN) reported topline data from a metastatic breast cancer treatment study. The results showed that Enhertu (trastuzumab deruxtecan) demonstrated a statistically significant and clinically meaningful improvement in progression-free survival (PFS) compared to standard-of-care chemotherapy in the primary trial population of patients with HR-positive, HER2-low (IHC 1+ or 2+/ISH-) metastatic breast cancer following one or more lines of endocrine therapy. A statistically significant and clinically meaningful improvement in PFS was also observed in the overall trial population (patients with HER2-low and HER2-ultralow [defined as IHC 0 with membrane staining; IHC >0<1+] metastatic breast cancer).  Related: AstraZeneca ...