AstraZeneca (LSE:AZN) said the FDA will extend the PDUFA date to review further data supporting its New Drug Application for camizestrant in combination with a CDK4/6 inhibitor for first-line HR-positive, HER2-negative advanced breast cancer with emergent ESR1 mutation.
The NDA is founded on positive Phase III SERENA-6 results presented at ASCO 2025 and published in The New England Journal of Medicine, and the FDA granted Breakthrough Therapy designation for the combination in May 2025.
In April 2026 the FDA's Oncologic Drugs Advisory Committee did not reach a majority vote in favour of the switching strategy tested in SERENA-6, and AstraZeneca has since supplied additional analyses requested by the agency, including ctDNA clearance data linked to longer-term efficacy outcomes.
"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," said Susan Galbraith, Executive Vice President, Oncology Haematology R&D, AstraZeneca.
SERENA-6 is a global, double-blind Phase III trial that enrolled 315 adults and compares camizestrant plus a CDK4/6 inhibitor versus an aromatase inhibitor plus a CDK4/6 inhibitor in patients whose tumours developed an emergent ESR1 mutation; the primary endpoint is investigator-assessed progression-free survival.
Camizestrant is an investigational next-generation oral selective estrogen receptor degrader in Phase III development, and earlier data from SERENA-2 and SERENA-1 showed a PFS benefit versus fulvestrant and a tolerable safety profile respectively.
The European Medicines Agency's CHMP adopted a positive opinion recommending approval on 22 May, camizestrant is approved in the UAE and Saudi Arabia, and applications are under review in Japan and other countries.
AstraZeneca will present the requested ctDNA clearance analyses on 02 June at ASCO 2026.
