PRIMARY OBJECTIVES:~I. Determine the efficacy of trifluridine/tipiracil hydrochloride combination agent TAS-102 (FTD/TPI [TAS-102]) in patients with refractory cholangiocarcinoma using progression-free survival at 16 weeks.~SECONDARY OBJECTIVES:~I. Assess the safety and tolerability of FTD/TPI (TAS-102) in patients with refractory cholangiocarcinoma through adverse event monitoring.~II. Further explore the efficacy of FTD/TPI (TAS-102) in patients with refractory cholangiocarcinoma by overall response rates, progression-free survival, and overall survival.~TERTIARY OBJECTIVES:~I. Determine if circulating tumor cells (CTCs) or cell-free deoxyribonucleic acid (DNA) (cfDNA) at baseline correlates with prognosis or response to therapy.~II. Determine if change in CTCs or cfDNA correlates with efficacy endpoints. III. Determine if different mutational status of the tumor will affect efficacy endpoints.~OUTLINE:~Patients receive trifluridine/tipiracil hydrochloride combination agent TAS-102 orally (PO) twice daily (BID) on days 1-5 and 8-12. Courses repeat every 28 days in the absence of disease progression or unacceptable toxicity.~After completion of study treatment, patients are followed up at 30 days and then every 3 months for up to 2 years.
This phase II trial studies how well trifluridine/tipiracil hydrochloride combination agent TAS-102 (TAS-102) works in treating participants with biliary tract cancers that have spread to other places in the body. Drugs used in the chemotherapy, such as trifluridine/tipiracil hydrochloride combination agent TAS-102, work in different ways to stop the growth of tumor cells, either by killing the cells, by stopping them from dividing, or by stopping them from spreading.