The study was stopped due to a realignment of strategic priorities

A national, multicenter, retrospective, observational study (Real-World Evidence-RWE) aimed to assess the efficacy of Trastuzumab-deruxtecan (T-DXd) in patients with triple-negative (RE<10%) metastatic HER2-Low breast cancer.

Data from study DESTINY-04 have established T-DXd as the standard second-line treatment for HER2-Low breast tumors. In that study, about 90% of the population had estrogen-positive receptor (ER+) tumors, under-representing negative ER population. The investigators propose to assess T-DXd efficacy in HER2-Low/ER ≤10% patients in Brazilian population by means of a RWE analysis. Endpoints will be assessment of time to the next treatment, objective response rate, and real-world progression-free survival and real-world overall survival.

Inclusion Criteria:

• Aged above 18 years old;
• Have advanced, hormone receptor negative (ER ≤10%), HER2-Low (1+ or 2+/FISH negative) breast cancer;
• Have been treated with at least one trastuzumab-deruxtecan dose for advanced disease (incurable) as a second or later line;
• Do not have active CNS metastatic lesions, characterized as stable, asymptomatic lesions and with no targeted treatment for at least 6 months.

Exclusion Criteria:

• Have been previously treated with trastuzumab-deruxtecan (neoadjuvant, adjuvant, other neoplasms);
• Have other active neoplasms (except from non-melanoma skin tumors);
• Have serious or active non-oncology lung diseases;
• Have other primary and concurrent breast tumor with differing receptor profiles.

Adult patients, with metastatic HER2-Low/ER ≤10% breast tumors, from Brazilian population, who were given TDXd as per usual prescription from their physician

Qualified researchers can request access to anonymized individual patient-level data from AstraZeneca group of companies sponsored clinical trials via the request portal Vivli.org. All requests will be evaluated as per the AZ disclosure commitment: https://astrazenecagrouptrials.pharmacm.com/ST/Submission/Disclosure.

"Yes", indicates that AZ are accepting requests for IPD, but this does not mean all requests will be approved.

AstraZeneca will meet or exceed data availability as per the commitments made to the EFPIA/PhRMA Data-Sharing Principles. For details of our timelines, please refer to our disclosure commitment at https://astrazenecagrouptrials.pharmacm.com/ST/Submission/Disclosure.

When a request has been approved AstraZeneca will provide access to the anonymized individual patient-level data via secure research environment Vivli.org. A Signed Data Usage Agreement (non-negotiable contract for data accessors) must be in place before accessing requested information.