[18F]FLT PET/CT in Rb+ Metastatic Breast Cancer

This protocol is designed to develop relationships between parameters determined from imaging
biomarker studies and ones used for determination of therapeutic response to combined CDK4
Inhibitor and chemotherapy regimens. Imaging will occur prior to starting therapy on the
separate therapeutic protocol UPCC 06115. Patients may undergo a second FLT PET/CT scan
following a 3-day run of ribociclib (LEE011) (day -6 to -4) and a third FLT PET/CT scan on
cycle 1 day 12 following two treatments of weekly Paclitaxel to compare changes in FLT uptake
measures.

Inclusion Criteria:

1. At least 18 years of age

2. History of histologically or cytologically confirmed breast cancer, any ER, PR or HER2
status is allowed as long as it expresses the Rb protein.

3. 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, MRI, FDG PET/CT, ultrasound, x-ray)

4. 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.

5. Patients must be candidates to receive treatment on the therapeutic trial UPCC06115, a
Phase I study of ribociclib (LEE011) and weekly paclitaxel.

Exclusion Criteria:

1. 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.

2. Inability to tolerate imaging procedures in the opinion of an investigator or treating
physician

3. 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.

4. Ineligible for the therapeutic trial UPCC 06115