This is a multicenter, single-arm, open-label, phase II clinical trial evaluating the efficacy and safety of dalpiciclib (a novel oral CDK4/6 inhibitor) combined with anti-HER2 therapy and endocrine therapy as maintenance treatment in patients with hormone receptor-positive (HR+)/HER2-positive metastatic breast cancer who have completed induction systemic therapy without disease progression.
Triple-positive (HR+/HER2+) metastatic breast cancer represents a unique subtype requiring dual pathway inhibition. Current standard first-line induction therapy includes taxane-based chemotherapy combined with trastuzumab and pertuzumab (THP) or pyrotinib (THPy), followed by maintenance with anti-HER2 therapy plus endocrine therapy. However, approximately 50% of patients progress within 18 months during maintenance therapy.
This study explores the addition of dalpiciclib to standard anti-HER2 and endocrine maintenance therapy to prolong progression-free survival. Dalpiciclib, the first domestically developed CDK4/6 inhibitor in China, has demonstrated favorable efficacy and a manageable safety profile in HR+/HER2- advanced breast cancer, with a lower incidence of febrile neutropenia and no observed interstitial lung disease.
