New breast cancer drug ‘reduces risk of disease progression or death’

AstraZeneca hails ‘groundbreaking’ results of Enhertu study

A new breast cancer drug reduces the risk of death or disease progression by 72 per cent compared to an existing treatment, AstraZeneca has announced.

The British company worked with another pharmaceutical giant on the drug, the Daiichi Sankyo Company, which has its headquarters in Japan. They said the results of its trial of Enhertu were “groundbreaking” and showed “a strong trend towards improved overall survival.”

Three-quarters of patients showed no progression in their disease after 12 months compared to 34.1 per cent of those treated with trastuzumab emtansine (T-DM1), while progression-free survival was improved from 7.2 months to 25.1 months.

Nearly all Enhertu patients were alive after 12 months (94.1 per cent), compared to 85.9 per cent of T-DM1 patients.

The phase 3 trial, which compared Enhertu’s performance against trastuzumab emtansine as a treatment for HER2-positive metastatic breast cancer, involved around 500 patients at multiple sites in Asia, Europe, North America, Oceania and South America.

Susan Galbraith, executive vice president of Oncology R&D at AstraZeneca, said: "Today's results are ground-breaking.

“These unprecedented data represent a potential paradigm shift in the treatment of HER2-positive metastatic breast cancer, and illustrate the potential for Enhertu to transform more patient lives in earlier treatment settings.”

Javier Cortes, from the International Breast Cancer Centre in Barcelona, said patients with previously treated HER2-positive metastatic breast cancer will typically experience disease progression in less than a year with available HER2-directed treatments.

He said the the "high and consistent benefit" seen across efficacy endpoints and key subgroups of patients receiving Enhertu is "remarkable and supports the potential of Enhertu to become the new standard of care for those who have previously been treated for HER2-positive metastatic breast cancer".

Ken Takeshita, global head of R&D at Daiichi Sankyo, said: "These landmark data will form the basis of our discussions with global health authorities to potentially bring Enhertu to patients with previously treated HER2-positive metastatic breast cancer as a more effective treatment option as soon as possible."

While breast cancer survival rates have doubled over the last four decades in the UK, every year around 11,500 women and 85 men die from the disease.

The Breast Cancer Now charity, which offers support and information on the disease, welcomed the results of the trial as “incredibly promising”.

Dr Kotryna Temcinaite, senior research communications manager, said: “It is fantastic to see that trastuzumab deruxtecan (Enhertu) could give hundreds of people with HER2 positive incurable secondary breast cancer the chance of more time before their disease progresses.

“We now hope that further research will show whether this treatment could also offer patients precious extra time to live and be there for more moments that matter. Anyone looking for support and information can speak to Breast Cancer Now’s expert nurses by calling our free Helpline on 0808 800 6000.”

Additional reporting by agencies

This article was amended on 19 September 2021 to remove the following sentence: ‘However AstraZeneca warned that the analysis is "not yet mature and is not statistically significant”.’ That warning was only referring to overall survival analysis, not the study as a whole. It was further amended on 7 October 2021 to add information about AstraZeneca’s collaboration with the Daiichi Sankyo Company.