AstraZeneca says FDA extends breast cancer drug review period

(Alliance News) - AstraZeneca PLC on Wednesday said that the US Food & Drug Administration has extended the review period for its camizestrant filing to allow time for the assessment of additional data related to the breast cancer treatment.

The Cambridge-based drugmaker said the FDA extended the prescription drug user fee act decision date for the new drug application covering camizestrant in combination with CDK4/6 inhibitors for the first-line treatment of patients with hormone receptor-positive, HER2-negative advanced breast cancer with emergent ESR1 mutations.

The application is based on positive results from the pivotal Serena-6 phase three trial, which were presented at the 2025 American Society of Clinical Oncology annual meeting and published in The New England Journal of Medicine.

AstraZeneca said the FDA granted breakthrough therapy designation for the treatment combination in May 2025.

However, the company noted that the FDA's Oncologic Drugs Advisory Committee in April did not reach a majority vote in favour of switching patients to camizestrant in combination with a CDK4/6 inhibitor after detecting ESR1 mutations before radiographic progression.

AstraZeneca said it subsequently submitted additional analyses requested by the FDA, including circulating tumour DNA clearance data linked to longer-term efficacy outcomes. These results are due to be presented at ASCO 2026 on June 2.

Executive Vice President for Oncology Haematology Research & Development Susan Galbraith said: "We look forward to continuing the dialogue with the FDA in order to bring the benefits of camizestrant with this innovative treatment strategy to eligible patients in the US as quickly as possible."

The company added that the European Medicines Agency's Committee for Medicinal Products for Human Use last week adopted a positive opinion recommending approval of the treatment combination in Europe.

Camizestrant has already been approved in the United Arab Emirates and Saudi Arabia, while applications remain under review in Japan and other markets.

Shares in AstraZeneca were down 0.1% at 13,952.00 pence in London on Wednesday morning.

By Eva Castanedo, Alliance News reporter

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