The FDA has notified AstraZeneca that it will extend the Prescription Drug User Fee Act (PDUFA) decision date for the new drug application (NDA) for camizestrant in combination with a cyclin-dependent kinase (CDK) 4/6 inhibitor for first-line treatment of hormone receptor‑positive, HER2‑negative advanced breast cancer with emergent ESR1 mutations. The extension will allow time to review additional data the agency requested to support the filing, which covers camizestrant used with palbociclib, ribociclib or abemaciclib in patients whose tumours develop ESR1 mutations during initial endocrine therapy plus a CDK4/6 inhibitor.
The NDA is supported by positive results from the pivotal SERENA‑6 Phase 3 trial, which were presented at the 2025 American Society of Clinical Oncology Annual Meeting and published in The New England Journal of Medicine. The FDA granted Breakthrough Therapy Designation to the camizestrant combination in this setting in May 2025.
In April 2026, the FDA’s Oncologic Drugs Advisory Committee did not reach a majority vote in favor of the benefit of switching to camizestrant plus a CDK4/6 inhibitor after detection of an ESR1 mutation in circulating tumor DNA (ctDNA) before radiographic progression, based on SERENA‑6 data. AstraZeneca has since submitted additional analyses requested by the agency, including ctDNA clearance data linked to longer-term efficacy outcomes that are scheduled to be presented on 2 June at ASCO 2026.
Susan Galbraith, executive vice president, Oncology Haematology R&D at AstraZeneca, said the company remains focused on advancing the oncology treatment landscape to improve patient outcomes. She described the SERENA‑6 strategy as monitoring patients for emerging ESR1 mutations in ctDNA and testing whether switching the endocrine backbone at that point can improve outcomes. Galbraith said AstraZeneca looks forward to continued dialogue with the FDA to bring the benefits of camizestrant and this treatment approach to eligible US patients as quickly as possible.
Outside the US, camizestrant is already progressing through regulatory channels. 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 indication based on SERENA‑6. Camizestrant is approved in the United Arab Emirates and Saudi Arabia in the same setting, and regulatory applications are under review in Japan and several other countries.
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