Pharma major AstraZeneca has received an extension in the US FDA review timeline for its investigational breast cancer therapy camizestrant, a next-generation oral selective estrogen receptor degrader (SERD) being evaluated for HR-positive, HER2-negative advanced breast cancer with ESR1 mutations.
The company said the US Food and Drug Administration (FDA) has pushed back the Prescription Drug User Fee Act (PDUFA) decision date to allow additional time for reviewing new data submitted from the Phase III SERENA-6 clinical trial. AstraZeneca noted that the extension is related to ongoing evaluation of supplementary efficacy analyses and does not involve any major new safety concerns.
Camizestrant is being developed in combination with CDK4/6 inhibitors for patients who develop ESR1 mutations during first-line endocrine therapy. The drug has attracted significant attention in oncology because it aims to intervene early, before visible disease progression appears on scans.
Last month, the FDA’s Oncologic Drugs Advisory Committee (ODAC) voted 6-3 against supporting the benefit-risk profile of camizestrant in this setting. Panel members raised concerns about whether switching therapy based on circulating tumor DNA (ctDNA) detection of ESR1 mutations provides enough long-term clinical benefit compared with waiting for radiographic progression.
Despite the regulatory setback in the US, AstraZeneca continues to highlight positive results from the SERENA-6 study. The trial demonstrated a 56% reduction in the risk of disease progression or death when camizestrant was combined with a CDK4/6 inhibitor, compared with standard endocrine therapy. Median progression-free survival reached 16 months versus 9.2 months in the control arm.
Meanwhile, Europe has taken a more supportive stance. The European Medicines Agency’s Committee for Medicinal Products for Human Use (CHMP) recently recommended approval of camizestrant for this indication, strengthening AstraZeneca’s global regulatory outlook.
The company stated it will continue working closely with the FDA and remains confident about the potential of camizestrant to address resistance-driven breast cancer progression. Additional long-term data from the SERENA-6 trial are expected to be presented at an upcoming medical meeting in early June.
