Trametinib or Combination Chemotherapy in Treating Patients With Refractory or Advanced Biliary or Gallbladder Cancer or That Cannot Be Removed by Surgery

This randomized phase II trial studies how well trametinib or combination chemotherapy works in treating patients with refractory or advanced biliary or gallbladder cancer or that cannot be removed by surgery. Trametinib may stop the growth of tumor cells by blocking some of the enzymes needed for cell growth. Drugs used in chemotherapy, such as fluorouracil, leucovorin calcium, and capecitabine, 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. It is not yet known whether giving trametinib is more effective than combination chemotherapy in treating patients with biliary or gallbladder cancer.