Biopharmaceutical company AstraZeneca plc (STO:AZN) (LON:AZN) (NYSE:AZN) announced on Wednesday that the US Food and Drug Administration (FDA) has extended the Prescription Drug User Fee Act decision date for camizestrant to allow review of additional supporting data for the SERENA-6 submission.

The application covers camizestrant in combination with a CDK4/6 inhibitor for first-line treatment of hormone receptor-positive, HER2-negative advanced breast cancer with emergent ESR1 mutation, based on results from the SERENA-6 Phase III trial presented at ASCO 2025 and published in The New England Journal of Medicine.

The FDA previously granted Breakthrough Therapy Designation in May 2025. Its Oncologic Drugs Advisory Committee did not reach a majority vote in April 2026 regarding the treatment benefit of switching therapy following ctDNA-detected ESR1 mutation prior to radiographic progression. AstraZeneca has since submitted additional FDA-requested analyses, including ctDNA clearance data linked to longer-term efficacy outcomes, which will be presented at ASCO 2026 on 2 June.

The European Medicines Agency's Committee for Medicinal Products for Human Use has issued a positive opinion recommending approval of the camizestrant combination in this setting based on the results of the SERENA-6 Phase III trial. The treatment is already approved in the United Arab Emirates and Saudi Arabia in this setting and it is under regulatory review in Japan and other markets.