This study is a randomized, controlled, open-label, multicenter, phase II superiority clinical trial. The planned study population consists of participants with HER2-positive recurrent or metastatic breast cancer who have not previously received systemic therapy for advanced disease (participants who have undergone one prior endocrine treatment regimen are eligible for enrollment). The study aims to compare the efficacy and safety of JSKN003 versus trastuzumab combined with pertuzumab and docetaxel as first-line treatment for participants with HER2-positive recurrent or metastatic breast cancer.
1Voluntary participation in this study and signing of the informed consent form (ICF).
Age ≥ 18 years.
Histologically and/or cytologically confirmed recurrent or metastatic breast cancer.
HER2-positive tumor status confirmed by the central laboratory (Positive definition: IHC 3+, or IHC 2+ with positive ISH).
Contraindications to trastuzumab, pertuzumab, and docetaxel, or deemed by the investigator as unsuitable for treatment with JSKN003.
Prior treatment with antibody-drug conjugates containing a topoisomerase I inhibitor (e.g., DS-8201, SHR-A1811, TQB-2102, etc.).
Toxicities from prior anti-tumor therapy have not recovered to ≤ Grade 1 per CTCAE 6.0 (except for toxicities judged by the investigator to pose no safety risk, such as alopecia, peripheral neuropathy, or isolated laboratory abnormalities, which must have resolved to ≤ Grade 2).
During prior anti-HER2 therapy, left ventricular ejection fraction (LVEF) decreased to <50%, symptomatic congestive heart failure occurred, or toxicity leading to permanent treatment discontinuation was experienced.