This study aims to compare the effects of the Bria-IMT regimen (a treatment plan) with a Checkpoint Inhibitor (CPI) called Retifanlimab against the treatment chosen by doctors for patients with advanced Metastatic Breast Cancer (aMBC). Metastatic means the cancer has spread to other parts of the body. Patients will be divided into groups to receive either the combination therapy (Bria-IMT + CPI), the doctor’s chosen treatment, or just the Bria-IMT regimen. Initially, the study includes 150 patients, after which the group receiving only Bria-IMT will switch to combination therapy if needed. Treatments in this study happen every 3 weeks, and the patient's health will be checked with imaging every 6 to 8 weeks.
- Duration: Treatment cycles every 3 weeks; imaging every 6-8 weeks.
- Eligibility: Participants must be 18 or older with specific cancer history.
- Exclusions: Recent other treatments, certain health conditions, or pregnancy.