(RTTNews) - Daiichi Sankyo Company, Limited (4568.T) announced that Japan's Ministry of Health, Labour and Welfare has approved Enhertu (trastuzumab deruxtecan) and Datroway (datopotamab deruxtecan) for new first-line indications in metastatic breast cancer.

Enhertu, in combination with pertuzumab, was approved for adults with HER2-positive unresectable or recurrent breast cancer, while Datroway was approved for adults with HR-negative, HER2-negative disease, commonly referred to as triple-negative breast cancer (TNBC).

Both Enhertu and Datroway are already approved in Japan for other breast cancer indications, with the latest decisions expanding their use to the first-line metastatic setting.

Breast cancer is the most common cancer among women in Japan. HER2-positive and TNBC are aggressive subtypes, with about 30% and 15% of patients, respectively, surviving five years after diagnosis.

Enhertu & Data Supporting Approval

Enhertu is a HER2-directed antibody-drug conjugate (ADC) comprising a HER2-targeting monoclonal antibody linked to a topoisomerase I inhibitor payload.

The approval was based on the Phase 3 DESTINY-Breast09 trial, in which Enhertu plus pertuzumab reduced the risk of disease progression or death by 44% versus taxane, trastuzumab and pertuzumab (THP). Median progression-free survival (PFS) was 40.7 months versus 26.9 months with THP.

Datroway & Data Supporting Approval

Datroway is a TROP2-directed ADC consisting of a TROP2-targeting monoclonal antibody linked to a topoisomerase I inhibitor payload.

The approval was supported by the Phase 3 TROPION-Breast02 trial in patients with metastatic TNBC who were not candidates for PD-1/PD-L1 inhibitor therapy. Datroway improved median overall survival (OS) by 5 months versus investigator's-choice chemotherapy, at 23.7 months versus 18.7 months. Median PFS was 10.8 months versus 5.6 months, with a 43% reduction in the risk of disease progression or death.

Both medicines carry a warning for interstitial lung disease (ILD) in Japan. Across multiple clinical trials, ILD occurred in 11.7% of patients treated with Enhertu and 3.1% of those treated with Datroway.

On Friday, Daiichi shares closed at JPPY 2,953.50, up 0.70%.