Enhertu and Datroway approved in Japan for two new 1L indications in metastatic Breast cancer

CAR-T Digest - August 2020

Weekly Digest - September 2026

16 September 2026: Enhertu and Datroway approved in Japan for two new 1L indications in metastatic Breast cancer

Daiichi Sankyo announced that Enhertu and Datroway have been approved in Japan for new first-line indications in metastatic breast cancer, with Enhertu plus pertuzumab approved for HER2-positive unresectable or recurrent breast cancer and Datroway approved for HR-negative/HER2-negative TNBC in patients who are not candidates for PD-1/PD-L1 inhibitor therapy
The Enhertu approval is based on the phase 3 DESTINY-Breast09 study, where Enhertu plus pertuzumab reduced the risk of disease progression or death by 44% versus THP (HR=0.56), with median PFS of 40.7 months versus 26.9 months; the Datroway approval is based on phase 3 TROPION-Breast02, where Datroway improved median OS to 23.7 months versus 18.7 months with chemotherapy (HR=0.79) and reduced the risk of progression or death by 43% (HR=0.57)
The approvals address a major unmet need in aggressive metastatic breast cancer subtypes, where HER2-positive and TNBC disease continue to have poor long-term outcomes and more effective first-line treatments are needed to delay disease progression and improve survival
Enhertu is a HER2-directed ADC comprising a HER2 monoclonal antibody linked to multiple topoisomerase I inhibitor DXd payloads through tetrapeptide-based cleavable linkers, while Datroway is a TROP2-directed DXd ADC designed to deliver the topoisomerase I inhibitor payload to TROP2-expressing tumor cells
Strategically, the approvals establish two Daiichi Sankyo DXd ADCs as first-line treatment options across HER2-positive and TNBC metastatic breast cancer in Japan, further expanding the company’s ADC franchise into earlier-line disease and reinforcing its position across major aggressive breast cancer subtypes