Camizestrant when an ESR1 mutation appears in advanced breast cancer
Slowed growth in one trial; survival benefit not yet shown.
What studies found
In SERENA-6 (315 patients with advanced hormone receptor-positive, HER2-negative cancer), people whose tumor developed an ESR1 mutation during first-line treatment switched to camizestrant before scans showed growth. Median progression-free survival was 16.0 months versus 9.2 with the original hormone drug. The FDA gave it accelerated approval in September 2026.
The catch
Accelerated approval means longer-term results are still needed; overall survival data are immature.
What to do
On first-line treatment for advanced hormone-positive breast cancer, ask whether ESR1 testing is planned.
Sources
Rung 3 of 5, Moderate: Consistent observational studies or small trials, not yet confirmed by large trials. How we score
Step by step
For the whole picture, from prevention and screening to treatment and life after, see the breast cancer page.
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