Company: AZN
Filing Date: 2025-04-22
Form Type: 6-K
Source: 0001654954-25-004504
Chunk: 2

Company: ASTRAZENECA PLC
Filing Date: 2025-04-22
Form: 6-K
Chunk 2
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 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.

Data from the combination arm of DESTINY-Breast09 will be presented at an upcoming medical meeting and shared with regulatory authorities.

Enhertu is already approved in more than 75 countries as 2nd-line treatment for patients with HER2-positive breast cancer based on the results from the DESTINY-Breast03 trial.

#### Notes

#### HER2-positive metastatic breast cancer
Breast cancer is the second most common cancer and one of the leading causes of cancer-related deaths worldwide. 7 More than two million breast cancer cases were diagnosed in 2022, with more than 665,000 deaths globally. 7 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. 8

HER2 is a tyrosine kinase receptor growth- promoting protein expressed on the surface of many types of tumours, including breast cancer. 9 HER2 protein overexpression may occur as a result of HER2 gene amplification and is often associated with aggressive disease in breast cancer. 1 Approximately one in five cases of breast cancer are considered HER2-positive. 10

While HER2-targeted therapies have improved outcomes, prognosis remains poor, with most patients experiencing disease progression within two years of 1st-line treatment with THP, which has been the standard of care for more than a decade. 2-4 Further, approximately one in three patients never go on to receive treatment following 1st-line therapy due to disease progression or death. 5,6

#### DESTINY-Breast09
DESTINY-Breast09 is a global, multicentre, randomised, open-label, Phase III trial evaluating the efficacy and safety of Enhertu (5.4mg/kg) either alone or in combination with pertuzumab versus standard of care THP (a taxane [docetaxel or paclitaxel], trastuzumab and pertuzumab) as a 1st-line treatment in patients with HER2-positive metastatic breast cancer.

Patients were randomised 1:1:1 to receive either Enhertu monotherapy with a pertuzumab matching placebo; Enhertu in combination with pertuzumab; or