WILMINGTON, Del.– AstraZeneca and Daiichi Sankyo’s cancer therapy ENHERTU® (fam-trastuzumab deruxtecan-nxki), when combined with pertuzumab, significantly extended progression-free survival compared to the long-standing standard treatment in patients with HER2-positive metastatic breast cancer, according to interim results from the Phase III DESTINY-Breast09 trial.
The study marks the first time in over a decade that any first-line treatment has shown superior efficacy across a broad population of patients with HER2-positive metastatic breast cancer compared to the current standard regimen of taxane, trastuzumab, and pertuzumab (THP).
The interim analysis demonstrated that ENHERTU plus pertuzumab delivered a highly statistically significant and clinically meaningful improvement in progression-free survival (PFS) across all predefined patient subgroups. While overall survival (OS) data are not yet mature, early trends suggest a potential survival benefit with the ENHERTU combination.
A second arm of the trial evaluating ENHERTU as a monotherapy remains blinded and will continue to a final PFS analysis.
HER2-positive metastatic breast cancer affects 15–20% of patients with advanced breast cancer and is characterized by aggressive disease progression. Despite advances in targeted therapies, most patients relapse within two years of starting THP, and up to one-third do not receive further treatment due to rapid disease progression or death.
“This is the first trial in more than 10 years to show superior efficacy across a broad patient population versus the first-line standard of care,” said Susan Galbraith, Executive Vice President of Oncology R&D at AstraZeneca. “These results represent a major step forward and lay the groundwork for using ENHERTU plus pertuzumab as a new frontline option.”
Ken Takeshita, Global Head of R&D at Daiichi Sankyo, emphasized the value of initiating therapy with ENHERTU earlier. “These findings suggest that using ENHERTU in combination with pertuzumab from the outset of metastatic diagnosis may delay disease progression and extend the time before additional treatments are needed.”
The safety profile of the combination therapy was consistent with known effects of the individual drugs.
ENHERTU, a HER2-directed antibody-drug conjugate developed by Daiichi Sankyo, is already approved in over 75 countries as a second-line treatment for HER2-positive breast cancer based on earlier trial results. Full data from DESTINY-Breast09 will be presented at an upcoming medical conference and submitted to health authorities for review.
