Overview

Given that pyrotinib has been proven to exert significant efficacy against HER2-positive advanced breast cancer in multiple Phase III studies, and the novel ADC drug disitamab vedotin has demonstrated potent anti-tumor activity, there remains insufficient real-world data on their sequential administration. This multicenter, prospective real-world study plans to enroll 500 patients with HER2-positive advanced breast cancer receiving first-line or second-line treatment. It aims to evaluate the efficacy and safety of sequential disitamab vedotin treatment after disease progression or intolerance to pyrotinib-based regimens (first-line: pyrotinib plus trastuzumab combined with chemotherapy; second-line: pyrotinib plus capecitabine). The primary endpoint is real-world second progression-free survival (rwPFS2), while secondary endpoints cover real-world progression-free survival (rwPFS), tumor response, overall survival (OS), time to treatment failure, safety profiles and patient-reported outcomes. It is currently expected to further validate the efficacy and safety of pyrotinib in patients with advanced HER2-positive breast cancer in the real-world setting, and to evaluate the efficacy and safety of recindopril trastuzumab following pyrotinib-containing regimens.

Eligibility

Inclusion Criteria:

1. Aged ≥ 18 years old;
2. Histopathologically confirmed HER2-positive inoperable locally advanced or metastatic breast cancer;
3. Patients with first-line or second-line advanced disease:

   First-line advanced disease: no prior systemic therapy for locally advanced or metastatic disease. For patients who received neoadjuvant or adjuvant therapy, the disease-free interval (DFI) after the completion of the last chemotherapy or HER2-targeted therapy was more than 12 months; Second-line advanced disease: prior treatment with taxane combined with trastuzumab, with or without pertuzumab, in the advanced setting; or recurrence occurring during neoadjuvant/adjuvant therapy, or a disease-free interval (DFI) of ≤ 12 months after completion of the last neoadjuvant/adjuvant chemotherapy and HER2-targeted therapy;

4. Planned to receive pyrotinib-containing regimen, and judged by investigators based on clinical practice to have potential subsequent treatment with Ruikang trastuzumab after failure of pyrotinib-containing therapy;
5. Traceable medical records available throughout the treatment period.

Exclusion Criteria:

1. Failure to sign the informed consent form;
2. Pregnant or lactating females;
3. Patients participating in any interventional clinical trial involving investigational drugs or marketed drugs at enrollment;
4. Other conditions deemed ineligible for enrollment by the investigator's judgment.