Study of Ribociclib With Everolimus + Exemestane in HR+ HER2- Locally Advanced/Metastatic Breast Cancer Post Progression on CDK 4/6 Inhibitor.

Inclusion Criteria

• Adult men and women
• Patient has a confirmed diagnosis of estrogen-receptor positive and/or progesterone receptor positive breast cancer by local laboratory and has HER2-negative breast cancer
• Patient must have either measurable disease by RECIST 1.1 or bone lesions in absence of measurable disease.
• ECOG Performance Status 0 - 1
• Disease refractory to either, AI, tamoxifen or fulvestrant
• Previously treated on any CDK 4/6 inhibitor.
• Patient has adequate bone marrow and organ function.

Exclusion Criteria

• Patient with symptomatic visceral disease or any disease burden that makes the patient ineligible for endocrine therapy per the investigator's best judgment.
• Patient has received more than one line of chemotherapy for advanced disease.
• Previous treatment with mTOR inhibitors, or exemestane for advanced disease.
• Progressed on more than one CDK 4/6 inhibitor
• Patient with CNS involvement unless they are at least 4 weeks from prior therapy completion.
• Clinically significant, uncontrolled heart disease and/or recent cardiac events.