Background: Intrahepatic cholangiocarcinoma (iCCA) is a cancer arising from the intrahepatic bile duct. Standard treatment of unresectable, recurrent, or metastatic iCCA is with cytotoxic chemotherapy. FGFR2 gene fusions have been identified as oncogenic drivers in 10–20% of iCCA tumors, but no targeted agents have been established to date. TAS-120 is an investigational irreversible FGFR1–4 inhibitor in development as a once-daily oral treatment for iCCA. Based on initial studies in multiple tumor types expressing FGFR abnormalities, iCCA was identified as a tumor type with potential susceptibility to FGFR inhibition and high unmet need. A phase I portion of the trial with an iCCA expansion cohort demonstrated tolerability and preliminary evidence of clinical efficacy with TAS-120 as a continuous, once-daily oral treatment in patients with iCCA. The most common AEs in the phase I portion of the trial were hyperphosphatemia, a mechanism-based on-target side effect, cutaneous AEs, and gastrointestinal AEs. The phase I portion of the study is continuing to enroll, and final results are anticipated in early 2019. Based on preliminary findings, a phase II portion of the study (FOENIX-101; clinicaltrials.gov registration NCT02052778) has been initiated. Methods: The phase II portion of the trial is a global, single-arm study of TAS-120 in patients with iCCA harboring FGFR2 gene rearrangements. The study will enroll approximately 100 adult patients with locally advanced or metastatic iCCA that progressed after ≥ 1 systemic therapies and with an ECOG PS of 0 or 1. Prior systemic therapy must include gemcitabine plus platinum-based chemotherapy. Screening for FGFR2 gene rearrangements will be performed at a central laboratory. The primary endpoint is objective response rate based on RECIST v1.1. Secondary endpoints include duration of response, disease control rate, overall survival, progression-free survival, safety, and health-related quality of life. Clinical trial information: NCT02052778