[18F]Fluorothymidine PET/CT Imaging for Monitoring Treatment Response in Patients with Metastatic Breast Cancer Undergoing Treatment with Ribociclib and Paclitaxel

Inclusion Criteria

• History of histologically or cytologically confirmed breast cancer, any estrogen receptor (ER), progesterone receptor (PR) or HER2 status is allowed as long as it expresses the Rb protein
• At least one site of metastatic breast cancer that is outside of the liver and bone that is identified by standard imaging (e.g. CT, magnetic resonance imaging [MRI], fludeoxyglucose F-18 [FDG] PET/CT, ultrasound, x-ray) and is measurable as defined by Response Evaluation Criteria in Solid Tumors (RECIST) 1.1
• Participants must be informed of the investigational nature of this study and provide written informed consent in accordance with institutional and federal guidelines prior to study-specific procedures
• Patients must be candidates to receive treatment on the therapeutic trial UPCC06115, a phase I study of ribociclib (LEE011) and weekly paclitaxel

Exclusion Criteria

• Females who are pregnant at the time of screening will not be eligible for this study, urine pregnancy test will be performed at screening in women of child-bearing potential
• Inability to tolerate imaging procedures in the opinion of an investigator or treating physician
• Serious or unstable medical or psychological conditions that, in the opinion of the investigator, would compromise the subject’s safety or successful participation in the study
• Ineligible for the therapeutic trial UPCC 06115