SEANGWORLD FACT BRIEF · SEANGWORLDNEWS · 1 SOURCE
FDA grants accelerated approval to Etcamah with CDK4/6 inhibitors for advanced HR-positive, HER2-negative breast cancer with ESR1 mutation
On September 4, 2026, the U.S. Food and Drug Administration granted accelerated approval to Etcamah (camizestrant) in combination with a CDK4/6 inhibitor (abemaciclib, palbociclib, or ribociclib) for treating adult patients with hormone receptor-positive, HER2-negative, locally advanced or metastatic breast cancer harboring ESR1 mutations detected during aromatase inhibitor and CDK4/6 inhibitor therapy. This approval is based on progression-free survival improvement, with median progression-free survival of 16 months for Etcamah plus CDK4/6 inhibitor versus 9.2 months for continued aromatase inhibitor plus CDK4/6 inhibitor. The FDA also authorized the Guardant360 CDx assay as a companion diagnostic to detect ESR1 mutations. Confirmatory studies are required to verify clinical benefit. A boxed warning addresses potential irregular heart rhythm risks with Etcamah.
Published ET · Updated ET
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Facts
- Established fact
FDA granted accelerated approval to Etcamah (camizestrant) in combination with a CDK4/6 inhibitor for treatment of adult patients with HR-positive, HER2-negative, locally advanced or metastatic breast cancer with ESR1 mutations detected during aromatase inhibitor and CDK4/6 inhibitor therapy.
- Established fact
ESR1 mutations represent acquired resistance mutations that may develop during aromatase inhibitor therapy in breast cancer patients.
- Established fact
Estimated median progression-free survival was 16 months with Etcamah plus CDK4/6 inhibitor versus 9.2 months with continued aromatase inhibitor plus CDK4/6 inhibitor.
- Established fact
The FDA authorized the Guardant360 CDx assay as a companion diagnostic to identify ESR1 mutations for treatment with camizestrant.
- Established fact
The FDA required confirmatory studies to verify and describe clinical benefit of Etcamah for this indication.
- Established fact
Etcamah carries a boxed warning for risk of irregular heart rhythm when taken with certain other medications, and warnings for slow heart rate and potential harm to unborn babies.
What changed
FDA approved a new treatment option, Etcamah in combination with CDK4/6 inhibitors, for HR-positive, HER2-negative advanced or metastatic breast cancer with ESR1 mutations.
Who is affected
Adult patients with hormone receptor-positive, HER2-negative, locally advanced or metastatic breast cancer exhibiting ESR1 mutations during aromatase inhibitor and CDK4/6 inhibitor therapy.
What happens next
Confirmatory studies are required to verify and describe clinical benefit of Etcamah in this indication.
Sources
1 SOURCE