Background: The majority of patients with intrahepatic cholangiocarcinoma (ICC) present with advanced liver dominant disease rendering them unresectable. The current standard of care supports palliative treatment of unresectable ICC with gemcitabine plus cisplatin. Alternatively, continuous liver-directed therapy using a surgically implanted hepatic arterial infusion (HAI) pump allows for maximal treatment of liver tumors with limited systemic side-effects and can facilitate conversion to a resectable status. No prospective clinical trial has utilized FOLFIRINOX in combination with HAI floxuridine-dexamethasone for ICC. Methods: HELIX-ICC is a first-line, single-center, single-arm, phase II clinical trial enrolling patients with liver-dominant unresectable or multifocal ICC. Only patients with microsatellite stable cancer and no prior liver radiotherapy will be included. Patients are administered dose-modified FOLFIRINOX systemically for 4 cycles over 8 weeks. Those with evidence of disease control on restaging imaging and laparoscopy will proceed to HAI pump placement. Treatment continues with two 28-day cycles of combined HAI floxuridine (1.08 mg/kg) with dexamethasone for 14 days and systemic dose-modified FOLFIRI starting on day 15. The primary objectives are to evaluate the safety and efficacy (disease control rate [DCR] at 6 months) of this novel treatment approach that utilizes our institutional dose-reduced HAI floxuridine protocol in combination with modified systemic regimens to facilitate control of liver disease and maximize patient quality of life (QoL). HELIX-ICC includes many exploratory analyses through longitudinal collection of blood samples, liver biopsies (including an end of trial research biopsy), and QoL metrics (Table). The study is open to n = 30 with an initial safety run-in of 6 patients, of which 4 have enrolled at the time of submission. This study is designed to allow for drop out of 9 patients, with total accrual of 21 patients to protocol completion achieving 80.2% power at 0.05 significance to detect a 25% increase in DCR at 6 months. Clinical trial information: NCT04251715.