AstraZeneca and Daiichi Sankyo’s Enhertu has been approved in the US for the treatment of adult patients with unresectable or metastatic HER2-low (IHC 1+ or IHC 2+/ISH-) breast cancer who have received a prior chemotherapy in the metastatic setting or developed disease recurrence during or within six months of completing adjuvant chemotherapy.

Enhertu is a specifically engineered HER2-directed antibody drug conjugate (ADC) being jointly developed and commercialised by AstraZeneca and Daiichi Sankyo.

“The rapid approval of Enhertuin HER2-low metastatic breast cancer by the FDA underscores the urgency to bring this transformational medicine to patients as quickly as possible. Patients with HER2-low tumours, who are identified through existing HER2 testing methods, will now have the opportunity to be treated based upon their HER2 status,” says Dave Fredrickson, Executive Vice President, Oncology Business Unit, AstraZeneca.

The DESTINY-Breast04 Phase III trial

The approval by the Food and Drug Administration (FDA) was based on the results from the DESTINY-Breast04 Phase III trial. In the trial, Enhertureduced the risk of disease progression or death by 50% versus physician’s choice of chemotherapy in patients with HER2-low metastatic breast cancer with hormone receptor (HR)-positive disease or HR-negative disease (median progression-free survival [PFS] 9.9 versus 5.1 months; hazard ratio [HR] 0.50; 95% confidence interval [CI] 0.40-0.63; p<0.0001). A median overall survival (OS) of 23.4 months was seen in patients treated with Enhertu versus 16.8 months in those treated with chemotherapy, a 36% reduction in the risk of death (HR 0.64; 95% CI 0.49-0.84; p=0.001).

Regulatory applications for Enhertu are also currently under review in Europe, Japan and several other countries based on the DESTINY-Breast04 results.

Photo of Dave Fredrickson: AstraZeneca