Study of Dalpiciclib Combined With Letrozole in the Maintenance Treatment of HR Positive and HER2 Negative Metastatic Breast Cancer After First-line Chemotherapy

A Multicenter, Single Arm, Prospective Phase II Clinical Study of Dalpiciclib Combined With Letrozole in the Maintenance Treatment of HR Positive and HER2 Negative Metastatic Breast Cancer After First-line Chemotherapy

This study aimed to evaluate the efficacy and safety of Dalpiciclib combined with Letrozole in the maintenance treatment of HR positive and HER2 negative metastatic breast cancer after first-line chemotherapy.

Inclusion Criteria:

1. Has the pathologically-confirmed diagnosis of locally recurrent or metastatic, hormone-receptor positive, HER2 negative Breast Cancer.
2. Age: 18 - 75 years old
3. Eastern Cooperative Oncology Group performance status (ECOG PS)=0~1
4. Functions of liver and kidney is normal
5. Agreed to take contraceptive measures during treatment

Exclusion Criteria:

1. Confirmed diagnosis of HER2 positive disease.
2. Central nervous system metastasis
3. Patients who received prior treatment with any CDK4/6 inhibitor.
4. Clinically significant cardiovascular and cerebrovascular diseases,including but not limited to severe acute myocardial infarction within 6 months before enrollment, unstable or severe angina, Congestive heart failure (New York heart association (NYHA) class > 2), or ventricular arrhythmia which need medical intervention；
5. Researchers believe that is not suitable for the study