First Astellas/AstraZeneca (AZN.US) blockbuster antibody-drug conjugate (ADC) Enhertu achieved positive results in a phase 3 clinical trial.

AstraZeneca (AZN.US) and Daiichi Sankyo Inc. recently announced positive results from the Phase 3 DESTINY-Gastric04 trial of Enhertu (trastuzumab deruxtecan), an antibody-drug conjugate (ADC) jointly developed by the two companies. In patients with HER2-positive unresectable and/or metastatic gastric or gastroesophageal junction adenocarcinoma, Enhertu, as a second-line therapy, achieved a statistically significant and clinically meaningful improvement in overall survival (OS) compared to the active comparator in the primary endpoint. At the pre-specified interim analysis, the independent data monitoring committee recommended unblinding the trial based on the positive efficacy of Enhertu. Enhertu is an ADC developed by AstraZeneca and Daiichi Sankyo. It is designed using Daiichi Sankyo's proprietary DXd ADC technology platform, which consists of a humanized monoclonal antibody targeting HER2 linked to a payload via a four-peptide cleavable linker and a topoisomerase 1 inhibitor. Gastric cancer is the fifth most common cancer worldwide and the fifth leading cause of cancer-related deaths. The prognosis of gastric cancer is poor, especially in the advanced stage, with a five-year survival rate of 5% to 10%. About one-fifth of gastric cancer is considered HER2-positive. The press release noted that historically, no HER2-targeted drugs have demonstrated survival benefit in the second-line setting after disease progression in first-line treatment of metastatic HER2-positive gastric cancer in randomized clinical trials.