Company: AZN
Filing Date: 2025-02-28
Form Type: 6-K
Source: 0001654954-25-002102
Chunk: 2

Company: ASTRAZENECA PLC
Filing Date: 2025-02-28
Form: 6-K
Chunk 2
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 developing and advancing the way breast cancer is classified and treated."

HER2 status in the trial was confirmed by a central laboratory and was performed on a tumour sample obtained at the time of initial metastatic diagnosis or later. Approximately 85-90% of patients with HR-positive, HER2-negative metastatic breast cancer were determined to be HER2-low or HER2-ultralow. 1

The safety profile of Enhertu in DESTINY-Breast06 was consistent with previous clinical trials of Enhertu in breast cancer with no new safety concerns identified.

Enhertu is a specifically engineered HER2-directed DXd antibody drug conjugate (ADC) discovered by Daiichi Sankyo and being jointly developed and commercialised by AstraZeneca and Daiichi Sankyo.

Enhertu was recently approved in the US for patients with HR-positive, HER2-low or HER2-ultralow metastatic breast cancer that has progressed on one or more endocrine therapies in the metastatic setting. In addition to the EU, regulatory applications are under review in Japan and several other countries based on the DESTINY-Breast06 results.

Enhertu is already approved in more than 75 countries, including the EU, for patients with HER2-low metastatic breast cancer who have received prior chemotherapy in the metastatic setting or developed disease recurrence during or within six months of completing adjuvant chemotherapy based on the results from the DESTINY-Breast04 trial.

#### Notes

#### Breast cancer and HER2 expression
Breast cancer is the second most common cancer and one of the leading causes of cancer-related deaths worldwide. 2 More than two million breast cancer cases were diagnosed in 2022 with more than 665,000 deaths globally. 2 In Europe, approximately 557,000 cases of breast cancer are diagnosed annually . 3 While survival rates are high for those diagnosed with early breast cancer, only about 30% of patients diagnosed with or who progress to metastatic disease are expected to live five years following diagnosis. 4

HER2 is a tyrosine kinase receptor growth-promoting protein expressed on the surface of many types of tumours, including breast cancer. 5 Patients with high levels of HER2 expression (IHC 3+ or 2+/ISH+) are classified as HER2-positive and treated with HER2-directed therapies, representing approximately 15-20% of all breast cancers. 6 Historically, tumours that were not classified as HER2-positive were classified as HER