Prognosis for unresectable intrahepatic cholangiocarcinoma (ICC) remains poor. Treatment combination known as Gemox (systemic chemotherapy of gemcitabine and oxaliplatin), along with lenvatinib and toripalimab, has shown favor results for ICC patients. However, Hepatic Arterial Infusion Chemotherapy (HAIC), which delivers chemotherapy directly to the liver, has also demonstrated benefits in controlling the cancer locally and improving survival for patients with ICC.

Based on these promising approaches, this study aims to find out if adding HAIC to the systemic chemotherapy-based treatment can help extending patients survival.

Inclusion Criteria:

• Histologically proven ICC with locally advanced or metastatic disease deemed unresectable by multidisciplinary evaluation; At least one measurable disease according to the Response Evaluation Criteria in Solid Tumors（RECIST v1.1）; Child-Pugh class A or B; ECOG performance status 0-1; Adequate bone marrow function（white blood cell count ≥2,000cells/mm3, hemoglobin > 9.0 g/dL, Platelet count ≥75,000/mm3）; Adequate hepatic and renal function (albumin ≥ 30 g/L, total bilirubin < 3 times the upper limit of normal, aspartate and alanine transaminases < 5 times the upper limit of normal, creatinine clearance rate of ≤ 1.5 times the upper limit of the normal) and coagulation function（PT < 18s, INR < 1.26）; written informed consent.

Exclusion Criteria:

• Life expectancy less than 2 months; concurrent other malignancy; Prior anticancer therapy (including chemotherapy, radiotherapy, surgery, or interventional treatments); Known allergy to chemotherapy drugs, lenvatinib or PD-(L)1 inhibitors; Patients with uncontrolled comorbidities, active infections; pregnancy or lactation; Refuse to comply with study and/or follow-up procedures; Gastrointestinal bleeding of any grade within 4 weeks prior to the treatment.