The Efficacy and Safety of CDK4/6 Inhibitors in Combination with Endocrine Therapy in the Neoadjuvant Treatment

Inclusion criteria

• Age ≥ 18 years old.
• Premenopausal and postmenopausal stage II-III females or males (patients with multicenter and/or multifocal early-invasive breast cancer) if all histopathological examination of tumors meet the pathological criteria of ER and/or PR>10% and HER2- (HER2 expression 0 or 1+ or 2+ and negative FISH test).
• Patients must have histologically confirmed ER and/or PR >10%, HER2-, early invasive breast cancer.
• Intolerance or insensitivity to neoadjuvant chemotherapy: 2 cycles of neoadjuvant chemotherapy, tumor evaluation PD/SD, advanced age, and inability to tolerate chemotherapy with underlying diseases.
• ECOG PS score 0-2.
• Patients must be able and willing to swallow and retain oral medications.
• Premenopausal women within 14 days of enrollment, or women with amenorrhea for less than 12 months at the time of enrollment, must have a negative serum or urine pregnancy test.
• Patients who have received neoadjuvant endocrine therapy are eligible for enrollment as long as they are enrolled within 6 months of initial histologic diagnosis and have completed no more than 2 months of neoadjuvant endocrine therapy.
• Absolute neutrophil count ≥ 1500/µL, platelet ≥ 100000/mm3, hemoglobin ≥ 10g/dL

Exclusion criteria

• Prior treatment with any CDK inhibitor.
• Inflammatory breast cancer or stage IV breast cancer or bilateral breast cancer.
• History of anaphylaxis caused by chemical or biologic components similar to dalsily.
• Patients who have received any drugs or substances with effective CYP3A isoenzyme inhibitors or inducers within 7 days of enrollment.
• Uncontrolled intercurrent illness that would limit compliance with study requirements.
• Pregnant women or women of childbearing potential with a negative pregnancy test within 14 days prior to admission.
• Patients with any history of malignancy are not eligible.
• Patients who have received endocrine therapy within 5 years prior to the diagnosis of the current malignancy.