Adults newly diagnosed with advanced lung cancer driven by a HER2 mutation went a median of 14.3 months before their disease worsened when their first treatment was Enhertu (trastuzumab deruxtecan), compared with 8.3 months on Keytruda plus chemotherapy. The results come from the phase 3 DESTINY-Lung04 trial presented in Seoul at the International Association for the Study of Lung Cancer's 2026 World Conference on Lung Cancer, held Sept. 12 to 15. Enhertu lowered the risk of cancer progression or death by 37%.
The finding applies to a small group that can be identified only through testing. HER2 mutations occur in roughly 2% to 4% of non-squamous non-small cell lung cancers, and AstraZeneca says they are seen mostly in younger women and people who have never smoked. These patients are found through biomarker testing of tumor tissue or blood, and Enhertu is not yet approved in the United States as a first treatment for this cancer.
