1816 – Genetic testing to detect estrogen receptor 1 (ESR1) variants in patients with hormone receptor (HR)-positive, HER-2 negative, locally advanced or metastatic breast cancer to determine eligibility for treatment with PBS subsidised camizestrant

New Medicare Benefits Schedule items for codependent application (MSAC and Pharmaceutical Benefits Advisory Committee).

This genetic test is to detect activating variants in the ESR1 gene in tumour tissue using circulating tumour DNA (ctDNA) extracted from a patient’s blood sample. The test is for patients with locally advanced or metastatic HR-positive, HER2-negative breast cancer, who have already received first-line treatment with a CDK4/6 inhibitor and an aromatase inhibitor for at least six months, and no disease progression on scans or through symptoms. Identifying ESR1 variants can help guide future treatment decisions and to determine eligibility for a potential PBS subsidised treatment, camizestrant.

Breast cancer is the abnormal growth of cells lining the breast lobules (milk-producing glands) or breast ducts (passages that drain milk from the lobules towards the nipple), or in the fatty and fibrous tissue of the breast. Hormone receptor (HR)-positive, HER2-negative breast cancer is a type of breast cancer that responds to hormones but does not have HER2 protein changes. In some cases, the cancer develops a variant in the ESR1 gene, which can affect how the cancer grows and how it responds to treatments. Variants in the ESR1 gene often occurs after treatment with a cyclin-dependent kinase 4/6 (CDK4/6) inhibitor and an aromatase inhibitor for at least six months. If the cancer has not shown signs of growth on scans or symptoms, it means the treatment is still working, but the ESR1 variant may influence future treatment choices.

The following consultation deadlines apply:

• Pre-PASC consultation deadline: Friday March 13 2026 11:59pm AEDT
• Pre-MSAC consultation deadline: To be confirmed

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This application will be considered at the following meetings:

• PASC meeting: 16 to 17 April 2026
• ESC meeting: To be confirmed
• MSAC meeting: To be confirmed

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The outcome of this application is pending.

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