By Fineline Cube 
Daiichi Sankyo (TYO: 4568) and AstraZeneca (AZ, NASDAQ: AZN) have submitted a supplemental new-drug application to China’s National Medical Products Administration seeking approval for Enhertu (trastuzumab deruxtecan, 100 mg/vial) as a second-line therapy for adults with HER2-positive gastric or gastro-esophageal junction adenocarcinoma, according to a statement released Wednesday. The filing has been granted priority review, marking the sixth indication pursued for Enhertu in China and the fourth to secure the expedited pathway.
Enhertu Mechanism and Development
Enhertu is an antibody-drug conjugate directed against human epidermal growth factor receptor 2 (HER2), jointly developed and commercialized by Daiichi and AstraZeneca. The construct comprises a humanized anti-HER2 IgG1 monoclonal antibody—identical in amino-acid sequence to trastuzumab—covalently linked via a stable tetrapeptide-based linker to the membrane-permeable topoisomerase I inhibitor DXd, a derivative of exatecan. Upon selective cleavage within tumor cells, the released payload translocates to the nucleus and disrupts DNA, triggering apoptosis. The therapy is already cleared in multiple markets for HER2-positive breast cancer, non-small-cell lung cancer, and gastric or GEJ adenocarcinoma.
Clinical Trial Basis
The China filing is based on data from the pivotal DESTINY-Gastric04 trial. In the primary overall survival analysis, Enhertu reduced the risk of death by 30% versus ramucirumab plus paclitaxel. A key secondary endpoint showed a 26% reduction in the risk of disease progression or death with Enhertu.-Fineline Info & Tech