AstraZeneca, Daiichi Sankyo get Enhertu FDA approval for HER2-low metastatic breast cancer

Enhertu FDA approval : AstraZeneca and Daiichi Sankyo have secured approval for Enhertu (trastuzumab deruxtecan) from the US Food and Drug Administration for the treatment of a type of metastatic breast cancer in adult patients.

Enhertu is said to be a specifically engineered HER2-directed antibody drug conjugate (ADC). It is being co-developed and commercialized by AstraZeneca and Daiichi Sankyo under a deal worth up to $6 billion signed in July 2020.

Its approval is for patients having unresectable or metastatic HER2-low breast cancer who had previously taken chemotherapy in the metastatic setting or developed recurrence of the disease during or within six months of the completion of adjuvant chemotherapy.

Enhertu FDA approval has been driven by the findings of the DESTINY-Breast04 phase 3 clinical trial. In the late-stage clinical trial, Enhertu cut down the risk of disease progression or death by 50% compared to physician’s choice of chemotherapy in patients having HER2-low metastatic breast cancer with hormone receptor (HR)-positive disease or HR-negative disease.

In patients subject to Enhertu treatment, the median overall survival (OS) was 23.4 months compared to 16.8 months in those subject to chemotherapy treatment, which is a reduction of 36% in the risk of death.

AstraZeneca, Daiichi Sankyo get Enhertu FDA approval for HER2-low metastatic breast cancer. Photo courtesy of AstraZeneca.

Commenting on Enhertu FDA approval, Dave Fredrickson — AstraZeneca Executive Vice President of Oncology Business Unit said: “The rapid approval of Enhertu in 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.”

Approvals for Enhertu are also being sought in Europe, Japan and other countries based on the results of the DESTINY-Breast04 clinical trial.

Following the Enhertu FDA approval, a milestone payment of $200m is to be paid by AstraZeneca to Daiichi Sankyo for the HER2-low breast cancer post chemotherapy indication. AstraZeneca made an upfront payment of $1 billion to the Japanese pharma company under the terms of the collaboration deal followed by other contingent payments.

Ken Keller, Daiichi Sankyo President and CEO and Global Head of Oncology Business said: “Today’s FDA approval marks a monumental moment in breast cancer treatment as Enhertu is the first-ever HER2-directed medicine to be approved for the treatment of patients with HER2-low metastatic breast cancer.

“With the ground-breaking survival benefit seen in the DESTINY-Breast04 trial, this milestone confirms the importance of targeting lower levels of HER2 expression in the treatment of metastatic breast cancer and we are thrilled that we can now offer Enhertu to even more patients.”