AstraZeneca and Daiichi Sankyo announced that the European Commission (EC) has approved Enhertu (trastuzumab deruxtecan) to treat a type of breast cancer in adults.

Enhertu is an antibody-drug conjugate (ADC) that contains humanised monoclonal antibody trastuzumab, covalently linked to the topoisomerase I inhibitor deruxtecan.

It is a specifically engineered HER2-directed antibody therapy being jointly developed and marketed by AstraZeneca and Daiichi Sankyo.

Enhertu is indicated for treating metastatic HER2-low breast cancer adult patients, who previously received chemotherapy, or experienced disease recurrence within six months.

AstraZeneca oncology business unit executive vice president Dave Fredrickson said: “Historically, patients with breast cancer who have tumours with low levels of HER2 expression have been classified as HER2-negative, giving them limited treatment options beyond chemotherapy.

“This approval reinforces the important role Enhertu may have for patients with HER2-low disease and highlights the need to evolve the way breast cancer is treated to improve patient outcomes.”

The EC approval follows a positive opinion of the Committee for Medicinal Products for Human Use (CHMP), based on results from Phase 3 DESTINY-Breast04 trial.

In the Phase 3 trial, Enhertu significantly reduced the risk of disease progression or death by 50%, and reduced the risk of death by 36%, compared to chemotherapy.

The drug resulted in a superior median progression-free survival (PFS) of 9.9 months, and a median overall survival (OS) of 23.4 months, compared to chemotherapy.

Enhertu showed a consistent safety profile in the DESTINY-Breast04 trial, compared to that seen in other Enhertu trials in breast cancer, with no new safety signals.

In relation with the EU approval, AstraZeneca is expected to make a milestone payment of $150m to Daiichi Sankyo.

Daiichi Sankyo president, CEO and oncology business global head Ken Keller said: “This milestone also supports our vision to bring Enhertu to more patients across the HER2 spectrum, which requires a change to the breast cancer classification system that has been guiding treatment for more than two decades.”

In a separate development, the US Food and Drug Administration (FDA) has revoked the Emergency Use Authorisation of AstraZeneca’s Evusheld for the prevention of Covid-19.

The US health agency’s move is based on the observation that Evusheld is not effective in retaining in-vitro neutralisation against the high frequency of circulating SARS-CoV-2 variants.