Efficacy and Safety of Dalpiciclib Plus Toremifene in the Treatment of Advanced First-line HR Positive and HER2 Negative Breast Cancer: a Multicenter, Single Arm, Exploratory Phase II Clinical Study

"1. Dalpiciclib : 150mg orally, once a day, taken for 3 weeks, stopped for 1 week, with a cycle of 4 weeks. It is recommended to take medication at the same time every day, with warm water for delivery. It is recommended to do so on an empty stomach and fast for at least 1 hour before and after taking the medication.~2. Toremifen: 60mg orally, once a day If it is a premenopausal or perimenopausal patient, it is necessary to combine with OFS (OFS includes bilateral ovariectomy or GnRHa drugs)."