AstraZeneca (AZ) and Daiichi Sankyo’s antibody drug conjugate (ADC) Enhertu has scored a conditional marketing authorisation in the UK for certain breast cancer patients.

The conditional marketing authorisation covers the use of Enhertu (trastuzumab deruxtecan) as a monotherapy for the treatment of adults with unresectable or metastatic HER2-positive breast cancer, who have received two or more prior anti-HER2 based regimens.

The UK authorisation is based on results from the Phase II DESTINY-Breast01 trial, in which patients treated with Enhertu demonstrated a confirmed objective response rate (ORR) of 61.4%, as well as a 6.5% complete response rate and a 54.9% partial response rate.

In addition, after a median follow-up of 20.5 months, the median duration of response (DoR) was 20.8 months.

“The DESTINY-Breast01 trial showed a duration of response not previously seen in patients after progression on first- and second-line treatment,” said Arun Krishna, head of oncology, AstraZeneca UK.

“Enhertu is an important new treatment option for patients at this stage of care and will shift clinical discussions towards a focus on targeted treatment. This is the first new cancer medicine to be authorised by the MHRA in 2021 and our focus now is on securing access for NHS patients as quickly as possible,” he added.

The UK’s National Institute for Health and Care Excellence (NICE) and the Scottish Medicines Consortium (SMC) are both currently appraising Enhertu, with NHS access decisions expected later in 2021.

In the UK, close to 54,000 cases of breast cancer in women are diagnosed each year – around one in five cases are HER2-positive.