Camizestrant Combination Delayed Time to First Progression by 55% and to Second Progression by 37% in Patients With Advanced HR-positive Breast Cancer With an Emergent ESR1 Tumor Mutation in SERENA-6 Trial
Switching to camizestrant led to a 99% median reduction in total ctDNA vs. a 64% increase for patients who remained on standard of care
51% of patients receiving the camizestrant combination achieved total ctDNA clearance vs. 1.9% with standard of care – early total ctDNA clearance was associated with an improvement in long-term outcome
WILMINGTON, Del.--(BUSINESS WIRE)-- Further positive results from the Phase III SERENA-6 trial showed AstraZeneca's camizestrant plus a cyclin-dependent kinase (CDK) 4/6 inhibitor – palbociclib, ribociclib or abemaciclib – maintained its progression-free survival (PFS) benefit with longer follow-up and delivered a statistically significant and clinically meaningful improvement in second progression-free survival (PFS2), demonstrating sustained benefit beyond initial treatment. Additionally, exploratory analyses showed that the camizestrant combination profoundly reduced total circulating tumor DNA (ctDNA) and enabled substantially more patients to achieve total ctDNA clearance.
The trial evaluated switching to the camizestrant combination before progression in the 1st-line setting versus continuing standard-of-care treatment with an aromatase inhibitor (AI) (anastrozole or letrozole) in combination with a CDK4/6 inhibitor following detection of an ESR1 mutation in patients with hormone receptor (HR)-positive, HER2-negative advanced breast cancer.
SERENA-6 met its primary endpoint of PFS at the interim analysis, with results first presented at last year’s American Society of Clinical Oncology (ASCO) and simultaneously published in The New England Journal of Medicine.1 The updated results will be presented today during the 2026 ASCO Annual Meeting in Chicago, IL (abstract LBA1007).
The updated results showed the camizestrant combination reduced the risk of disease progression or death by 55% versus an AI plus a CDK4/6 inhibitor (based on a hazard ratio [HR] of 0.45; 95% confidence interval [CI] 0.34-0.59; p
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