A Study of HLD-0117 in Patients With Metastatic Breast Cancer

Inclusion Criteria

• •Female (assigned at birth), ≥18 years old, and able to provide informed consent
• •Histologically confirmed metastatic or locally advanced breast cancer
• •Postmenopausal status defined by surgical or natural menopause, or ovarian suppression with a GnRH agonist
• •Prior treatment including at least one endocrine therapy in the metastatic setting, at least one CDK4/6 inhibitor (in the adjuvant and/or metastatic setting), and no more than two prior cytotoxic regimens in the metastatic setting
• •Radiologic disease progression on the most recent therapy
• •Measurable disease per RECIST v1.1
• •Willingness to provide baseline and on-treatment tumor biopsies, unless not feasible or medically appropriate
• •ER-positive and HER2-negative status documented within 2 years
• •ECOG performance status 0-1 and life expectancy of at least 3 months
• •Adequate organ function Recovery from prior therapy-related toxicities to Grade ≤1 (except alopecia; neuropathy and endocrinopathies ≤Grade 2)
• •Ability to swallow oral medication and comply with study procedures
• •Stable dose (≥30 days) of bisphosphonates or denosumab, if applicable