This phase II trial studies whether [18F]FTT can be used with positron emission tomography (PET)/computed tomography (CT) imaging to predict treatment response in patients scheduled to receive gemcitabine, cisplatin, and durvalumab (GCD) for newly diagnosed cholangiocarcinoma. PET/CT is an imaging technique that utilizes PET and CT in a single machine. PET is an established imaging technique that utilizes small amounts of radioactivity attached to very minimal amounts of tracer, in the case of this trial, [18F]FTT, to make detailed, computerized pictures of areas inside the body where the tracer is used. CT utilizes x-rays that traverse body from the outside. CT images provide an exact outline of organs and potential inflammatory tissue where it occurs in the patient's body. [18F]FTT targets and binds to poly (ADP-ribose) polymerase 1 (PARP1). Some cholangiocarcinoma tumor cells may express PARP1 which may make it easier to see them on PET/CT. Research has shown that tumor cells that express PARP1 may not respond well to GCD treatment. Researchers hope that by using [18F]FTT with PET/CT imaging they will be able to detect which patients have tumor cells that express PARP1, which may help predict treatment response in patients scheduled to receive GCD for newly diagnosed cholangiocarcinoma.

OUTLINE:

Patients receive [18F]FTT intravenously (IV) and 60, 90, or 150 minutes later undergo PET/CT within 30 days prior to day 1 cycle 1 of GCD and 12 weeks after starting GCD in the absence of unacceptable toxicity. Patients also undergo CT and/or magnetic resonance imaging (MRI) throughout the study.

After completion of study intervention, patients are followed up at week 24 and then up to 6 months after completing GCD treatment.

Inclusion Criteria:

• Patient must have histologically confirmed cholangiocarcinoma
• Patient must be newly diagnosed and have not yet been treated
• Patient planned to receive GCD per standard-of-care
• Patient must have evaluable disease or at least one measurable lesion that can be assessed at baseline by CT (or MRI) per RECIST 1.1
• Age ≥ 18 years
• For women of childbearing potential, a negative serum pregnancy test is required within 7 days prior to [18F]FTT PET imaging
• Men and women of reproductive potential need to agree to employ acceptable forms of contraception throughout their participation in the study that meet requirements for GCD treatment per standard of care
• Patient is willing and able to comply with the protocol for the duration of the study including undergoing all study procedures
• Ability to understand and the willingness to sign a written informed consent document. Informed consent must be provided prior to any study specific procedures

Exclusion Criteria:

• Pregnant or breastfeeding women
• Uncontrolled intercurrent illness including, but not limited to, ongoing or active infection, symptomatic congestive heart failure, unstable angina pectoris, cardiac arrhythmia, or psychiatric illness/social situations that would limit compliance with study requirements