AstraZeneca and Daiichi Sankyo’s Enhertu, in combination with pertuzumab, has been approved by the US FDA to treat adult patients with unresectable or metastatic HER2-positive breast cancer.
The approval follows previous Priority Review and Breakthrough Therapy designations from the FDA. It is based on data from the phase 3 DESTINY-Breast09 trial, which enrolled 1,157 patients across multiple sites in Europe, the US, Asia, Africa and South America.
The trial found that Enhertu in combination with pertuzumab reduced the risk of disease progression or death by 44% compared to a taxane, trastuzumab and pertuzumab (THP) combination treatment. Median progression-free survival (PFS) was 40.7 months for patients treated with Enhertu plus pertuzumab, compared to 26.9 months for patients treated with THP.
The safety profile of Enhertu plus pertuzumab was found to be consistent with the established individual safety profiles of each drug.
Sara Tolaney, a principal investigator for the trial, said: “Trastuzumab deruxtecan plus pertuzumab is the only first-line treatment approved in more than a decade to demonstrate a statistically significant improvement in progression-free survival over the current standard regimen for patients with HER2-positive metastatic breast cancer.”
HER2-positive breast cancer occurs in around one in five breast cancer cases; its metastatic form is driven by overexpression or amplification of the tyrosine kinase receptor growth-promoting protein HER2. Prognosis for HER2-positive breast cancer remains poor, with most patients experiencing disease progression within two years of first-line treatment with THP.
Enhertu is a HER2-directed antibody drug conjugate (ADC) discovered by Daiichi Sankyo and jointly developed and commercialised by AstraZeneca and Daiichi Sankyo.
Dave Fredrickson, executive vice president, Oncology Haematology Business Unit at AstraZeneca, said: “With this approval, we are bringing Enhertu to the earliest setting for HER2-positive metastatic breast cancer, where optimising efficacy has an important impact on long term outcomes.
“The treatment approach with Enhertu plus pertuzumab in DESTINY-Breast09 sets a new benchmark of more than three years without disease progression or death for patients in this setting.”