US FDA pushes back decision date for SERENA-6 filing of camizestrant to allow review of additional data

The US FDA has notified AstraZeneca that it will extend the Prescription Drug User Fee Act (PDUFA) date in order to review additional data requested in support of the New Drug Application (NDA) for camizestrant in combination with a cyclin dependent kinase (CDK) 4/6 inhibitor (palbociclib, ribociclib, or abemaciclib) for the first line treatment of patients with hormone receptor (HR) positive, HER2 negative advanced breast cancer whose tumours have developed an emergent ESR1 mutation.

The NDA is supported by positive findings from the pivotal SERENA-6 Phase III trial, which were presented at the 2025 American Society of Clinical Oncology (ASCO) Annual Meeting and published simultaneously in The New England Journal of Medicine. The camizestrant combination was granted Breakthrough Therapy Designation in this setting by the FDA in May 2025.

In April 2026, the FDA’s Oncologic Drugs Advisory Committee did not reach a majority vote in favour of the benefit of switching to camizestrant in combination with a CDK4/6 inhibitor after detection of an ESR1 mutation in circulating tumour DNA (ctDNA) prior to radiographic progression, based on the SERENA-6 Phase III trial. Since then, the Company has supplied further analyses requested by the FDA in support of the application, including ctDNA clearance data linked to longer term efficacy outcomes, which will be presented on 2 June at ASCO 2026.

Susan Galbraith, Executive Vice President, Oncology Haematology R&D, AstraZeneca, said: “We are committed to continuously advancing the clinical landscape in oncology in pursuit of improving outcomes for patients. The SERENA-6 treatment strategy epitomises this approach by monitoring patients for the emergence of ESR1 mutations in ctDNA and testing if a switch of endocrine backbone therapy at this point improves outcomes. 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.”

On 22 May, the European Medicines Agency’s Committee for Medicinal Products for Human Use adopted a positive opinion recommending approval of the camizestrant combination in this setting, based on the SERENA-6 Phase III results.

Camizestrant is currently approved in the United Arab Emirates and Saudi Arabia in this setting. Regulatory applications are also under review in Japan and several other countries, all based on the SERENA-6 Phase III trial.

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Related Topics and Keywords

AstraZeneca, camizestrant, FDA Approval, SERENA-6 filing