A Phase I/II Trial to Evaluate Oral HP568 Tablets in Patients with ER+/HER2 Advanced Breast Cancer

Prior treatment

• Within 42 days prior to the first administration, Fluvistran was used; Other endocrine therapies such as tamoxifen, toremifene, letrozole, anastrozole, and exemestane were used within 14 days prior to the first administration.
• Previously received other ER-ROTAC drugs such as ARV-471.
• Within 6 weeks before the first administration of HP568 in this study, nitrosoureas or mitomycin were used; Received any anti-tumor treatment, including immunotherapy, chemotherapy, radiotherapy, or targeted therapy, within 28 days prior to the first administration (or of the drug's 5 half lives,take the shorter one).

Other illness

• Known or suspected allergy to any ingredient of HP568 formulation, and allergy to any ingredient of palbociclib (only applicable to stage III).

• Women aged 18-75 years old (inclusive of both ends) at the time of signing the informed consent form.
• Patients with locally advanced inoperable or recurrent or metastatic breast cancer ER+/HER2- advanced breast cancer is confirmed by histopathology have confirmed that the primary and/or metastatic lesion.
• Previously received at least 1-line endocrine therapy (endocrine therapy duration ≥ 6 months) and ≤ 2-line chemotherapy (≤ 2-line chemotherapy limited to dose escalation stage) for the recurrence or metastasis stage of the disease. The third stage : Inclusion of patients who have not received prior treatment but are suitable for CDK4/6i therapy.
• Disease progression confirmed by imaging occurs during or after the last systemic anti-tumor treatment before the first medication.