Efficacy and Safety of SPH4336 in Combination With Endocrine Therapy in Breast Cancer Patients With Brain Metastases.

Inclusion Criteria:

1. Patients who voluntarily participate in this study, completely understand thisstudy, and voluntarily sign the informed consent form (ICF).

2. ECOG (Eastern Cooperative Oncology Group) performance status score of 0 or 1.

3. Life expectancy ≥ 3 months.

4. Patients with locally advanced or metastatic breast cancer who are unable to receiveradical surgeries/other local therapies.

5. At least one measurable lesion .

6. Laboratory test results meet the relevant requirements for organ function.

7. Subjects who agree to take effective contraceptive measures.

Exclusion Criteria:

1. Inflammatory breast cancer.

2. Patients unsuitable for endocrine therapy at the investigator's discretion.

3. Have a History of other malignancies prior to the start of study treatment.

4. Taking anti-tumor traditional Chinese patent medicines at the time of signing theICF.

5. Patients who underwent a surgery prior to the start of study treatment, and have notyet recovered from adverse reactions of the surgery.

6. Patients who participated in a clinical trial and received other investigationaldrugs before the start of study treatment.

7. Pregnant or lactating women.

8. History of myocardial infarction, unstable angina pectoris, severe arrhythmia, andsymptomatic congestive heart failure before the start of study treatment; ≥ NYHA (New York Heart Association) Class II; QTcF≥ 470 ms; left ventricular ejectionfraction ≤ 50%.

9. History of ischemic stroke or severe thromboembolic disease before the start ofstudy treatment.

10. Hepatitis B surface antigen positive and HBV (Hepatitis B Virus) DNA > 2,000 IU/mLor > 10(4) copies/mL; HCV (Hepatitis C Virus) antibody positive and HCV RNApositive; or known HIV infection.

11. History of severe allergic diseases, history of severe drug allergies, or knownallergy to any ingredient of the investigational product.

12. Presence of diseases or conditions that may impact drug administration orgastrointestinal absorption before the start of study treatment.

13. Presence of uncontrolled infections before the start of study treatment.

14. Known history of drug abuse, excessive drinking, or illegal drug use; history ofconfirmed neurological or mental disorders.

15. Presence of other diseases that the risks of receiving the study treatment outweighits benefits, as determined by the investigator, or any other reason for whichpatients are ineligible for the study as assessed by the investigator.