Biopharmaceutical company AstraZeneca PLC (STO: AZN; LON: AZN; NYSE: AZN) said on Monday that US regulators have granted accelerated approval for Etcamah (camizestrant), its next-generation oral selective oestrogen receptor degrader, to be used with a CDK4/6 inhibitor in adults with HR-positive, HER2-negative advanced breast cancer who develop an ESR1 mutation during first line aromatase inhibitor and CDK4/6 inhibitor therapy.

The FDA has also approved a companion diagnostic to identify ESR1 mutations in circulating tumour DNA.

The decision follows results from the SERENA-6 Phase III trial, which showed a 56% reduction in the risk of disease progression or death versus standard treatment. The trial enrolled 315 patients and AstraZeneca said it is the first global Phase III study to use circulating tumour DNA to detect emerging ESR1 mutations and guide an early switch in endocrine therapy before clinical progression.

In the interim analysis, median progression-free survival was 16 months for the Etcamah combination compared with 9.2 months for an AI plus CDK4/6 inhibitor. A subsequent planned analysis reported a statistically significant PFS2 benefit of 25.7 months versus 19.1 months, while overall survival data continued to mature in favour of the Etcamah regimen.

Safety outcomes were consistent with the known profiles of the individual medicines, with low and comparable discontinuation rates across both trial arms.

Etcamah is already authorised in more than 30 countries, including in the EU, Japan, Canada and the UK, based on SERENA-6 data.