A Phase I/II, Open-label study to assess the safety, tolerability, pharmacokinetic, and antitumor efficacy of FWD1802 monotherapy in patients with ER+/HER2- unresectable locally advanced or metastatic breast cancer. This clinical trial aims to explore the role of FWD1802 in the ER+/HER2- advanced breast cancer patient population. The primary objectives are to address the following questions:
Phase I Study:
Determine the Recommended Phase II Dose (RP2D) and/or Maximum Tolerated Dose (MTD) of FWD1802 in patients with ER-positive, HER2-negative locally advanced or metastatic breast cancer.
Phase II Study:
To evaluate the efficacy of FWD1802 at the RP2D in patients with ESR1-mutated ER-positive/HER2-negative locally advanced or metastatic breast cancer, using objective response rate (ORR) as the efficacy endpoint.
Voluntarily participate in the clinical trial and sign the informed consent form.
Female, aged ≥18 years.
Able to provide blood samples for central laboratory testing of ESR1 mutation status and other biomarker assessments. Phase I Study: ESR1 mutation status will be tested retrospectively. Phase II Study: Only subjects with confirmed ESR1 mutations will be enrolled (see Appendix 5 for details).
Histologically or cytologically confirmed locally advanced or metastatic breast cancer that is ER-positive and HER2-negative.
Leptomeningeal metastases, carcinomatous meningitis, spinal cord compression, or symptomatic or clinically unstable central nervous system (CNS) metastases.
Inability to swallow oral medications.
Requirement for intravenous nutrition.
Prior surgery affecting absorption, including total/partial gastrectomy.