A Study of XZP-3287 in Combination With Letrozole/Anastrozole in Patients With Advanced Breast Cancer

Inclusion criteria

• Female patients aged ≥18 years and ≤75 years old;
• Patient is in the menopausal state；
• Histologically or cytologically confirmed locally advanced, recurrent or metastatic breast cancer, which was pathologically confirmed to be HR-positive and HER2-negative;
• Evidence of locally advanced, recurrent, or metastatic disease that is not amenable to curative surgical resection or radiation therapy and is not clinically amenable to chemotherapy;
• No prior systemic anticancer therapy for locally advanced, recurrent, or metastatic disease;
• At least one measurable lesion (based on RECIST v1.1) or only bone metastases;
• Patient has an Eastern Cooperative Oncology Group (ECOG) performance status 0 or 1;
• Adequate organ and marrow function;
• Patient of childbearing age must undergo a serum pregnancy test within 7 days before randomization, and the result is negative; patient is willing to use a medically approved high-efficiency contraceptive method during the study period and within 6 months after the last study drug treatment;
• Patient with acute toxic reactions caused by previous anti-tumor treatments or surgical operations were alleviated to grade 0 to 1 (NCI-CTCAE v5.0), or to the level specified by the enrollment criteria;
• Patient has signed informed consent before any trial related activities.

Exclusion criteria

• Patients with disease recurrence or metastasis at or within 12 months after previous neoadjuvant or adjuvant therapy with endocrine drugs;
• Patient with visceral crisis or brain metastases, except for patient with stable brain metastases;
• Patient had clinically significant pleural effusions, ascites effusions, or pericardial effusions in the 4 weeks before enrollment;
• Patient who received prior treatment with mTOR inhibitors or CDK4/6 inhibitors ;
• Participation in a prior treatment of major surgery, chemotherapy, radiotherapy, and any anti-tumor treatment within 14 days before enrollment；
• Patient who participated in other clinical trials within 14 days before enrollment or within 5 half-lives of the trial drug, whichever is longer;
• Patient used CYP3A4 potent inhibitors or potent inducers within 14 days before enrollment or within 5 half-lives of the drug, whichever is longer;
• Initiation of bisphosphonates or RANKL inhibitors within 7 days before enrollment, and subjects who have initiated treatment > 7 days before enrollment should not change the method of use;
• Any other malignant tumor has been diagnosed within 5 years before randomization;
• Patient is in the active stage of HBV, HCV or co-infected with HBV, HCV, or Patient with positive HIV antibody;
• Patient with severe infection within 4 weeks before enrollment, or unexplained fever> 38.3℃ during screening/before enrollment;
• Patient with heart function impaired or clinically significant heart disease within 6 months before enrollment;
• Cerebrovascular accident occurred within 6 months before enrollment, including history of transient ischemic attack or stroke; pulmonary embolism;
• Inability to swallow, intestinal obstruction or other factors that affect the taking and absorption of the drug;
• Patient with a known hypersensitivity to any of the excipients in this study;
• A prior history of autologous or allogeneic hematopoietic stem cell transplantation;
• A prior history of psychotropic drug abuse or drug use;
• Nursing Mothers;
• The researchers considered that there were some cases that were not suitable for inclusion.