Biopharmaceutical company AstraZeneca PLC (STO: AZN; LON: AZN; NYSE: AZN) announced on Thursday it has secured European Union approval for Etcamah (camizestrant) combined with a CDK4/6 inhibitor for adults with ER-positive, HER2-negative locally advanced or metastatic breast cancer who develop an ESR1 mutation without progressing on 1st-line endocrine therapy.

The decision follows a positive Committee for Medicinal Products for Human Use opinion and is supported by SERENA-6 Phase III data published in The New England Journal of Medicine. Etcamah is also approved in Japan, the United Arab Emirates and Saudi Arabia, with further regulatory reviews ongoing, including in the US.

In an interim analysis, the Etcamah combination cut the risk of disease progression or death by 56% versus an aromatase inhibitor plus CDK4/6 inhibitor, with median progression-free survival of 16.0 months compared with 9.2 months.

SERENA-6 also showed a statistically significant improvement in time to second progression of 25.7 months versus 19.1 months, while overall survival continues to mature in favour of the Etcamah regimen. Safety findings were consistent with known profiles of the medicines and discontinuation rates were low in both arms.

AstraZeneca said the trial is the first global Phase III study to use circulating tumour DNA to detect emerging endocrine resistance and guide an early switch in therapy before clinical progression. It enrolled 315 patients with HR-positive, HER2-negative advanced disease receiving 1st-line aromatase inhibitor therapy with a CDK4/6 inhibitor.

Breast cancer remains the leading cause of cancer death among women in Europe, with more than 140,000 deaths in 2024, and ESR1 mutations are a key driver of endocrine resistance, emerging in around 30% of patients during 1st-line treatment.