Enhertu plus pertuzumab showed 44% reduction in disease progression risk in HER2-positive breast cancer

Published June 2, 2025

AstraZeneca and Daiichi Sankyo announced results from the DESTINY-Breast09 Phase III trial, showing the combination of Enhertu (trastuzumab deruxtecan) and pertuzumab significantly improved progression-free survival (PFS) compared to standard chemotherapy (THP) as a first-line treatment for patients with HER2-positive metastatic breast cancer.

The trial data, presented at the 2025 American Society of Clinical Oncology (ASCO) Annual Meeting, revealed a 44% reduction in the risk of disease progression or death for patients treated with Enhertu plus pertuzumab versus THP. The median PFS in the Enhertu arm was 40.7 months, compared to 26.9 months for THP. This marks the first trial in over a decade to show improved outcomes in the first-line setting for this patient population.

Objective response rates (ORR) were also higher with the Enhertu combination, at 85.1%, compared to 78.6% for THP. The median duration of response (DOR) exceeded three years at 39.2 months for Enhertu plus pertuzumab, versus 26.4 months for THP. While overall survival (OS) data was not yet mature, interim results indicated a trend favoring the Enhertu combination.

Clinical investigators noted that these findings suggest Enhertu plus pertuzumab has the potential to become a new standard of care for initial treatment of HER2-positive metastatic breast cancer, addressing a critical need for earlier intervention and improved long-term outcomes for patients.