- DESTINY-Breast09 phase 3 trial of Daiichi Sankyo and AstraZeneca’s ENHERTU is the first trial in more than a decade to demonstrate superior efficacy across a broad HER2 positive metastatic patient population versus current first-line standard of care
- Plans for regulatory submissions are underway
Positive topline results from a planned interim analysis of the DESTINY-Breast09 phase 3 trial showed ENHERTU® (trastuzumab deruxtecan) in combination with pertuzumab demonstrated a highly statistically significant and clinically meaningful improvement in progression-free survival (PFS) compared to taxane, trastuzumab and pertuzumab (THP) as a first-line treatment for patients with HER2 positive metastatic breast cancer.
ENHERTU is a specifically engineered HER2 directed DXd antibody drug conjugate (ADC) discovered by Daiichi Sankyo (TSE: 4568) and being jointly developed and commercialized by Daiichi Sankyo and AstraZeneca (LSE/STO/Nasdaq: AZN).
The PFS improvement was seen across all pre-specified patient subgroups with ENHERTU in combination with pertuzumab. The key secondary endpoint of overall survival (OS) was not mature at the time of this planned interim analysis; however, interim OS data showed an early trend favoring the ENHERTU combination compared to THP.
The second arm assessing ENHERTU monotherapy versus THP remains blinded to patients and investigators and will continue to the final PFS analysis.
HER2 positive metastatic breast cancer is an aggressive disease driven by overexpression or amplification of HER2 that affects 15% to 20% of patients with metastatic breast cancer.1 While HER2 targeted therapies have improved outcomes, prognosis remains poor with most patients experiencing disease progression within two years of first-line treatment with THP, which has been the standard of care for more than a decade.2,3,4,5 Further, approximately one in three patients never go on to receive treatment following first-line therapy due to disease progression or death.6,7
“The results of DESTINY-Breast09 reinforce the importance of effectively targeting HER2 to achieve durable disease control early in the treatment of HER2 positive metastatic breast cancer,” said Ken Takeshita, MD, Global Head, R&D, Daiichi Sankyo. “Building on the positive results seen with ENHERTU in the second-line setting, these new findings suggest that starting treatment with ENHERTU in combination with pertuzumab at the time of metastatic diagnosis delays disease progression, postponing the time until additional treatment may be needed.”
“This is the first trial in more than a decade to demonstrate superior efficacy across a broad HER2 positive metastatic breast cancer patient population compared to the current first-line standard of care,” said Susan Galbraith, MBBChir, PhD, Executive Vice President, Oncology Hematology R&D, AstraZeneca. “This is a significant milestone for patients and sets the foundation for ENHERTU in combination with pertuzumab as an important treatment option in the first-line HER2 positive setting.”
The safety profile of ENHERTU in combination with pertuzumab was consistent with the known profiles of each individual therapy.
Data from the combination arm of DESTINY-Breast09 will be presented at an upcoming medical meeting and shared with regulatory authorities.
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