Background: Dysregulation of fibroblast growth factor receptor (FGFR) signaling by FGFR translocations and activating mutations is implicated in many cancers, including CCA. FGFR2 translocation, the most common FGFRalteration, occurs in ~13% of pts with intrahepatic CCA. INCB054828 is a novel, orally available, selective inhibitor of FGFR1, FGFR2, and FGFR3 tyrosine kinase activity (AACR 2015; Abstract 771). Methods: This phase 2, open-label trial will evaluate INCB054828 monotherapy in pts with advanced/metastatic or unresectable CCA (NCT02924376). Pts will be prescreened locally or centrally for FGF/FGFR status prior to enrollment (Table): FGFR2 translocation (Cohort A); other FGF/FGFR alteration (Cohort B); no FGF/FGFR alteration (Cohort C; negative control for effects of FGF/FGFR alteration on objective response rate [ORR]). Eligibility criteria include: age ≥18 years; ECOG performance status ≤2; adequate liver and renal function; life expectancy ≥12 wks; disease progression after ≥1 prior systemic therapy; no prior use of selective FGFR inhibitors. Pts will self-administer INCB054828 orally at a starting dose of 13.5 mg QD on a 21-day cycle (2 wks on; 1 wk off); treatment will continue until disease progression or unacceptable toxicity. The primary endpoint will be ORR (complete or partial response, independent radiologic review committee, RECIST v1.1) in pts with FGFR2 translocation (Cohort A). Secondary endpoints include ORR in pts positive or negative for any FGF/FGFRalteration and duration of response, PFS, OS, and safety (all cohorts). The study has currently enrolled 2 pts (recruitment ongoing; estimated primary completion, April 2018). Clinical trial information: NCT02924376