Daiichi Sankyo and AstraZeneca's ENHERTU has received breakthrough therapy designation (BTD) from the US Food and Drug Administration (FDA) for the treatment of a specific type of metastatic breast cancer.

ENHERTU is intended for patients with unresectable or metastatic hormone receptor-positive HER2 low (IHC 1+ or IHC 2+/ISH-) or HER2 ultralow (IHC >0 <1+) breast cancer.

Eligible patients should have received two previous lines of endocrine therapy in the metastatic setting, or a single line of endocrine therapy if they showed disease progression within six months of beginning first-line treatment with endocrine therapy along with a CDK4/6 inhibitor or within 24 months of the commencement of adjuvant endocrine therapy.

An antibody-drug conjugate,  ENHERTU is developed by Daiichi Sankyo and co-commercialised with AstraZeneca. It targets HER2, a protein associated with aggressive breast cancer.

The FDA granted the designation based on preliminary results from the global, randomised, open-label Phase III DESTINY-Breast06 trial.

It compared the efficacy and safety of ENHERTU against standard chemotherapies.

This trial involved 866 patients across Asia, Europe, North America, Oceania and South America.

With this latest BTD, ENHERTU has now received eight such designations, four of which are for metastatic breast cancer.

Previous BTDs were granted for later-line HER2 low, second-line HER2 positive and later-line HER2 positive metastatic breast cancers.

Daiichi Sankyo research and development global head Ken Takeshita stated: “If approved, ENHERTU could once again change the treatment paradigm for certain patients with breast cancer, pushing past old boundaries and broadening the number of people who may be eligible for a HER2-directed therapy.

“The designation also showcases Daiichi Sankyo’s commitment to pioneering cutting-edge science to deliver medicines like ENHERTU that create new standards of care for patients with cancer.”