The goal of this multicentre, randomized, double-blind controlled, phase III clinical trial is to compare the efficacy and safety of disitamab vedotin in combination with pyrotinib versus the standard first-line treatment of paclitaxel in combination with trastuzumab and pertuzumab (THP) for newly diagnosed recurrent/metastatic Human epidermal growth factor receptor 2 (HER2) positive advanced breast cancer, and to explore the impact of biomarkers on clinical efficacy and safety. The main questions it aims to answer are:
* Analyse the efficacy and safety of disitamab vedotin in combination with pyrotinib versus the standard first-line treatment of THP. * Explore the impact of biomarkers on clinical efficacy and safety of the combination of disitamab vedotin in combination with pyrotinib treatment.
Participants in the experimental group will receive disitamab vedotin in combination with pyrotinib for 6-8 cycles (each cycle lasting 28 days), followed by maintenance treatment with trastuzumab in combination with pyrotinib. Participants in the control group will receive paclitaxel in combination with trastuzumab and pertuzumab for 6-8 cycles (each cycle lasting 21 days), followed by maintenance treatment with trastuzumab and pertuzumab.
Researchers will compare disitamab vedotin in combination with pyrotinib versus the standard first-line treatment of paclitaxel in combination with trastuzumab and pertuzumab to see if disitamab vedotin in combination with pyrotinib could be a new option for first-line treatment of HER2-positive metastatic breast cancer.
Adult female patients (age 18-75 years) with metastatic breast cancer confirmed by pathology or imaging;
Pathologically confirmed HER2 positive (definition: Immunohistochemistry(IHC) 3+, or IHC 2+ and Fluorescent In Situ Hybridization(FISH) amplification);
No previous chemotherapy regimen for metastatic breast cancer;
At least one measurable lesion exists (Response Evaluation Criteria in Solid Tumors(RECIST) 1.1);
Pathology suggestive of HER2 negativity (IHC 2+ and FISH-, or IHC 1+);
Patients with known hypersensitivity to the active ingredient or other components of the study drug;
Patients during pregnancy or lactation, patients with childbearing potential tested positive in a baseline pregnancy test, or patients unwilling to take effective contraceptive measures throughout the trial;
Patients not eligible for this study judged by the investigator, a pre-existing disease or condition that may interfere with participation in the study or any serious medical disorder that may interfere with the safety of the subject (e.g., uncontrolled heart disease, high blood pressure, active or uncontrolled infections, active hepatitis B virus infection).