This is an open, multicenter, randomized controlled clinical study aimed to explore the efficacy and safety of chidamide combined with exemestane (+/- goserelin) versus chemotherapy in the neoadjuvant treatment of stage II-III HR +/HER2- breast cancer patients with poor response to previous chemotherapy.

Inclusion Criteria:

• female patients aged greater than or equal to 18 years and less than or equal to 75 years, meet one of the following:

  1. previous oophorectomy, or age ≥ 60 years;
  2. age < 60 years, natural postmenopausal status (defined as at least 12 consecutive months of spontaneous cessation of regular menstruation, and no other pathological or physiological causes), E2 and FSH in postmenopausal levels;
  3. premenopausal or perimenopausal female patients, must be willing to receive LHRH agonist therapy during the study;

• all patients were confirmed by histopathology as estrogen receptor (ER) positive (> 10%), HER2 receptor negative.Follow the 2018 version of ASCO-CAP HER2-negative interpretation guideline criteria;

• tumor stage II-III meeting the AJCC 8th version criteria, patients who have previously received 2 cycles of TE regimen chemotherapy, with disease evaluation of SD or PD;

• KPS score ≥ 70 points;

• organ function level must meet the following requirements:

  1. bone marrow function ANC ≥ 1.5 × 109/L (14 without growth factors); PLT ≥ 100 × 109/L (7 without corrective treatment); Hb ≥ 100 g/L (7) without corrective treatment;
  2. liver and kidney function TBIL ≤ 1.5 × ULN; ALT and AST ≤ 3 × ULN; BUN and Cr ≤ 1.5 × ULN and creatinine clearance ≥ 50 mL/min (Cockcroft-Gault formula);

• able to undergo needle biopsy;

• voluntarily join this study, sign informed consent, have good compliance and are willing to cooperate with follow-up

Exclusion Criteria:

• received any form of anti-tumor therapy (chemotherapy, radiotherapy, molecular targeted therapy, endocrine therapy, etc.);
• received any other anti-tumor therapy at the same time;
• breast cancer, inflammatory breast cancer or occult breast cancer;
• stage IV breast cancer;
• breast cancer without histopathological diagnosis;