Albumin-bound Paclitaxel、Dalpiciclib and AI in ER-Low (1%-10%) HER2-ABC

This is a prospective, single-arm, single-center, open, exploratory clinical study. Simon two-stage sample size calculation was used in this study, and the primary endpoint was objective response rate (ORR). P0=37.3% (POLAMA-4 experimental group data), P1=53.2%, unilateral α=0.05, 1-β=80% were set. PASS15 software was used to calculate 21 cases in the first stage, with a total sample size of 52 cases. If 8 patients in Phase I achieve an objective response, proceed to Phase II. Screening for histopathologically confirmed recurrent or metastatic ER-Low positive (1%-10%) and HER2-negative (IHC 0/1+ or IHC 2+ but ISH-) breast cancer patients who meet the inclusion criteria and have not previously received any systemic anticancer therapy for advanced disease, He was treated with albumin-bound paclitaxel in combination with Dalpiciclib and AI.