Zionexa US Corp.

Eclectic is a strategy trial; once the class of treatment (endocrine therapy or chemotherapy) has been allocated according to 16α-18F-fluoro-17β-oestradiol (18F-FES) Positron Emission Tomography/Computed Tomography (PET/CT) results and circulating tumor biomarkers, clinicians will decide which treatment to use.

This is a phase 4, multi-center, open-label, prospective cohort study to evaluate the clinical utility of Fluoroestradiol F18 (Cerianna) PET/CT to guide therapeutic management in ER-positive, HER2-negative metastatic breast cancer patients with progressive disease on first-line standard-of-care hormonal therapy. All patients will undergo a Cerianna PET/CT scan. The treating physician will complete a standardized questionnaire to indicate the second-line therapeutic management plan before the scheduled Cerianna PET/CT. After interpretation of Cerianna PET/CT by local radiologist or nuclear medicine physician, the treating physician will fill out a similar questionnaire to specify the final therapeutic decision. The proportion of patients with a change in therapeutic management plan based on Cerianna PET/CT results will be the primary endpoint. During the study follow-up period of 18 months, data on standard-of-care imaging, treatments/procedures received, and clinical outcomes will be collected. Patients will be asked to complete a health-related quality of life questionnaire at their screening, 6-month, and 18-month visit. Secondary endpoints include visual and quantitative heterogeneity assessment of tumor Cerianna uptake, and PFS rates at 6 months and 18 months after Cerianna PET/CT, which will be assessed between patients with and without a change in therapeutic management plan. Maximum duration of follow-up for each patient: 20 months. First patient first visit to last patient last visit: estimated 36 months.