# FDA approvals for ESR1-mutated breast cancer

> Live situation record from CLSTR: https://clstr.news/situations/fda-approvals-for-esr1-mutated-breast-cancer
> Updated: 2026-10-07T08:36:51.000Z. Sources: 4. Developments: 2.

The U.S. Food & Drug Administration has expanded treatment options for hormone receptor-positive/HER2-negative metastatic breast cancer by approving therapies targeting ESR1 mutations.

In September 2026, the FDA granted accelerated approval to Etcamah (camizestrant), a next-generation oral selective estrogen receptor degrader (SERD). Clinical trials indicated that using Etcamah in combination with a CDK4/6 inhibitor resulted in a median progression-free survival of 16 months, compared to 9.2 months when using an aromatase inhibitor plus a CDK4/6 inhibitor.

Following this, the FDA approved a combination of imlunestrant and abemaciclib for patients with ESR1-mutated advanced or metastatic breast cancer who have progressed after previous endocrine therapy. Medical experts noted that these developments allow the molecular evolution of cancer to guide treatment, as ESR1 mutations often emerge as a mechanism of resistance to aromatase inhibitors.

## Timeline

### 2026-10-07: FDA approvals advance treatment for ESR1-mutated breast cancer

New FDA approvals for imlunestrant and abemaciclib offer new treatment pathways for patients with ESR1-mutated metastatic breast cancer.

2 sources. https://clstr.news/cluster/fda-approvals-advance-treatment-for-esr1-mutated-breast-cancer

### 2026-09-09: FDA approves Etcamah for ESR1-mutated breast cancer

The FDA has approved Etcamah (camizestrant) for HR-positive/HER2-negative breast cancer patients with ESR1 mutations, showing improved progression-free survival in clinical trials.

2 sources. https://clstr.news/cluster/fda-approves-etcamah-for-esr1-mutated-breast-cancer

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Cite as: FDA approvals for ESR1-mutated breast cancer. CLSTR, https://clstr.news/situations/fda-approvals-for-esr1-mutated-breast-cancer