International Breast Cancer Biomarker,Standard of Care and Real World Outcomes Study

Background/Rationale: Within the setting of metastatic human epidermal growth factor receptor
2 negative (HER2-ve) breast cancer limited epidemiological data exist on the prevalence of
pathogenic mutations of breast cancer susceptibility gene (BRCA) and other homologous
recombination repair (HRR) genes. There are also limited data on the treatments and clinical
outcomes of patients with such germline and somatic genetic profiles, particularly within
this setting. This epidemiologic study will estimate the prevalence of germline breast
susceptibility gene (gBRCA) mutations among metastatic HER2-ve patients who have commenced
1st line systemic cytotoxic chemotherapy and, at that time, are considered to have exhausted
hormone therapy options (if hormone receptor positive [HR+ve]), per investigator's opinion.
Among those patients with a gBRCA gene mutation, treatment patterns and clinical outcomes
will be described. This study may also explore the prevalence of somatic BRCA (sBRCA)
mutations and other HRR gene mutations among metastatic HER2-ve patients who have commenced
1st line systemic cytotoxic chemotherapy. The treatment patterns and clinical outcomes may be
described among those patients with a sBRCA gene mutation and those with other HRR gene
mutations.

Inclusion Criteria:

1. Provision of signed, written and dated informed consent.

2. Adult females (according to the age of majority/adulthood as defined by local
regulations).

3. Histologically or cytologically confirmed HER2-ve breast cancer with evidence of
metastatic disease.

4. Initiated treatment with 1st line systemic cytotoxic chemotherapy (not hormonal
therapy) for metastatic breast cancer in the last 90 days and, at that time, are
considered to have exhausted hormone therapy options (if HR+ve).

Exclusion Criteria:

1. Previous enrolment in this study.

2. Involvement in the planning and/or conduct of this study (applies to both AstraZeneca
staff and/or staff at the study site).

3. Current participation in a clinical study with an investigational oncology product.

4. Previous PARPi therapy, including, but not limited to, participation in a previous
clinical study that included PARPi therapy.

5. Current commencement of PARPi treatment.