This is a phase II,single center,prospective, single arm clinical trial. The objective is to evaluate the efficacy and safety of routine therapy plus moxifloxacin in Advanced Breast Cancer whose evaluation is stable disease with a trend of progression.

This is a phase II,single center,prospective, single arm clinical trial. A lot of in vitro and in vivo study demonstrate that quinolones antibiotics can increase anti-tumor effect. The objective is to evaluate the efficacy and safety of routine therapy plus moxifloxacin in Advanced Breast Cancer whose evaluation is stable disease with a trend of progression.

Inclusion Criteria:

• Female ≥ 18 years, ≤70 years.
• Has measurable metastatic MBC, with at least 1 measurable lesion per RECIST criteria.
• Fail first-line or above anti-tumor treatment
• Evaluation is stable disease with a trend of progression.
• Minimum life expectancy 16 weeks
• Histological confirmation of breast cancer on primary tumour at diagnosis/on biopsy of metastasis
• ECOG Performance Status (PS) 0-2 with no deterioration over previous 2 weeks
• Normal organ function.
• Has signed a Patient Informed Consent Form

Exclusion Criteria:

• Hypersensitivity to moxifloxacin or other quinolones.
• Tendon damage,peripheral neuropathy,myasthenia gravis.
• Rapidly progressive visceral disease not suitable for further therapy.
• Evidence of severe or uncontrolled systemic diseases, including uncontrolled hypertension, active bleeding diatheses, or active infection including hepatitis B, hepatitis C and HIV
• With the exception of alopecia, any unresolved toxicities from previous therapy greater than CTCAE grade 1 before study treatment
• Evidence of dementia, altered mental status or any psychiatric condition that would prohibit understanding or rendering of informed consent
• Inability or unwillingness to comply with study procedures, including inability to take regular oral medication
• Researchers consider it is not suitable for participation.