Exploration of Dalpiciclib Plus HDACi in HR+/HER2- Advanced Breast Cancer After Failure of CDK4/6 Inhibitor

Exclusion Criteria

• •1. Previously received treatment with histone deacetylase inhibitor (HDACi);
• •2. Previously received Dalpiciclib;
• •3. MRI or lumbar puncture confirmed leptomeningeal metastasis;
• •4. Central nervous system metastasis is confirmed by imaging; The following conditions will be excluded: 1) asymptomatic brain metastases without immediate radiotherapy or surgery; 2) Previously received local treatment (radiotherapy or surgery) for brain metastases, stable for at least 4 weeks, and no symptomatic treatment (including glucocorticoids, mannitol, bevacizumab, etc.) for more than 2 weeks with clinical symptoms;
• •5. The participants presented with visceral crisis (such as lymphangitis carcinomatosis, bone marrow replacement, leptomeningeal metastasis, diffuse liver metastasis with abnormal liver function), rapid disease progression, and that is not suitable for endocrine therapy;
• •6. Participants had ascites, pleural effusion and pericardial effusion with clinical symptoms at baseline, which required drainage within 4 weeks before the first medication;
• •7. Inability to swallow, intestinal obstruction, or other factors that affect medication administration and absorption;
• •8. Subjects that are diagnosed with any other malignancy within 5 years prior to the study, excluding non-melanoma skin cancer treated with radical therapy, basal or squamous cell skin cancer or carcinoma in situ of the cervix and papillary thyroid.
• •9. The subject has undergone major surgery or major trauma or is expected to undergo major surgery within 4 weeks before the start of treatment;
• •10. A known history of allergy to the drug ingredient of this protocol.