What is your preferred second-line of treatment for metastatic gallbladder carcinoma after progression on gemcitabine/cisplatin in a young, fit patient?

There is currently no standard of care for second-line therapy in biliary tract cancers after front-line cisplatin/gemcitabine. During front-line therapy, I routinely send these tumors for molecular profiling, as targetable mutations are relatively common in biliary tract cancers and differ based on location of tumor (intrahepatic, extrahepatic, gallbladder). If a patient has an actionable mutation found during molecular profiling, my preferred second-line therapy option would be a clinical tria...