Pyrotinib Combined With Trastuzumab and Pertuzumab for Maintenance Therapy in HER2-Positive Advanced Breast Cancer

Inclusion Criteria

• •1. Age ≥ 18 years, male or female.
• •2. Histologically or cytologically confirmed HER2-positive advanced breast cancer (IHC 3+, or IHC 2+ with ISH amplification), with known HR status.
• •3. Have unresectable locally advanced or metastatic disease. If recurrent (after \[neo\]adjuvant therapy), must be at least 6 month treatment free from any trastuzumab and pertuzumab received in the early breast cancer setting for advanced HER2+ disease.
• •4. Have received 4-8 cycles of pre-study induction therapy including only trastuzumab, pertuzumab, and taxane as first-line of therapy for the treatment of advanced breast cancer prior to study enrollment. Participants are eligible provided they are without evidence of disease progression following completion of induction therapy.
• •5. CNS Inclusion - Based on screening contrast-enhanced brain magnetic resonance imaging (MRI), participants may have any of the following: No evidence of brain metastases. Untreated brain metastases which are asymptomatic not needing immediate local treatment and, if identified on prior brain imaging, without evidence of progression since starting first-line induction therapy with trastuzumab, pertuzumab, and taxane
• •6. Eastern Cooperative Oncology Group (ECOG) Performance Status of 0-2
• •7. Have planned to receive maintenance anti-tumor therapy with pyrotinib in combination with HP
• •8. Negative serum pregnancy test; women of childbearing potential must use a highly effective contraceptive method from study initiation until at least 6 months after the last dose of study medication.
• •9. Voluntary participation with written informed consent obtained prior to any study-related procedures.