Abstract: ObjectiveTo investigate the efficacy and safety of chidamide combined with paclitaxel liposome in the treatment of advanced breast cancer with negative HER2 expression. 
MethodsA total of 41 patients with advanced HER2 negative breast cancer from May 2017 to November 2017， who failed in 2 regimens of chemotherapy were enrolled and randomly divided into observation group （n=20） and control group （n=21）. Patients in observation group were given chidamide tablets （30 mg oral administration， twice per week for 2 months） and paclitaxel liposome （175 mg／m2 iv， 21 days was a cycle for 3 cycles）. In addition to paclitaxel liposome, patients in control group were given placebo （30 mg oral administration， twice per week for 2 months）. Response rate， disease control rate and progressionfree survival were analyzed. 
ResultsAll patients were evaluable for the efficacy. In observation group， there were 5 cases of CR， 7 cases of PR， 5 cases of SD and 3 cases of PD. RR was 600％ and DCR was 850％. In control group， there were 3 cases of CR， 3 cases of PR， 5 cases of SD and 10 cases of PD. RR was 286％ and DCR was 524％. The RR and DCR in observation group were higher than those in control group （P＜005）. The median PFS was 52 months in observation group， higher than 31 months in control group （P＜005）. The main adverse reactions were gastrointestinal reactions and bone marrow suppression， mainly in grade 12. The incidences of leukopenia， thrombocytopenia and nausea／vomiting were higher in observation group than in control group （P＜005）. 
ConclusionChidamide combined with paclitaxel liposome for advanced breast cancer with negative HER2 expression has good efficacy and the adverse effects are tolerable.

Key words: Breast cancer, Negative HER2 expression, Chidamide, Paclitaxel liposome