Background: Fibroblast growth factor (FGFR) alterations occur in 10-15% of adult patients with advanced intrahepatic cholangiocarcinoma (CCA) and 1-2% of adult patients with advanced extrahepatic cholangiocarcinoma. The first generation FGFR inhibitors (FGFRi) pemigatinib and futibatinib, have been approved for the treatment of advanced CCA with FGFR2 fusions or rearrangements after systemic chemotherapy. However, disease progression occurs within 6-9 months. Secondary polyclonal mutations in the FGFR kinase domain represent a prominent acquired resistance mechanism. Tinengotinib, a novel multi-kinase inhibitor with high potency against a variety of FGFR2 kinase domain mutations, has shown promising clinical benefit in subjects with FGFR-altered metastatic CCA who were heavily pretreated with chemotherapy and FGFRi(s) in phase I/II clinical trials. (NCT03654547, NCT04742959, NCT04919642). Methods: FIRST-308 is a phase III, randomized, global multicenter study to evaluate the efficacy and safety of oral tinengotinib versus Physician’s Choice in subjects with FGFR-altered, chemotherapy- and FGFRi-refractory/relapsed CCA. Approximately 200 subjects will be enrolled in US, Europe, and Asia. Key eligibility criteria include age ≥ 18 years, ECOG performance status 0 or 1, documentation of FGFR2 fusion/rearrangement gene status, prior treatment with at least one line of chemotherapy and exactly one prior FDA-approved FGFRi for unresectable or metastatic disease. The study includes Part A and Part B. The Part A is to select a dose for Part B. Eligible subjects will be randomized in a 2:2:1 ratio to receive tinengotinib 8 mg QD, tinengotinib 10 mg QD or Physician's Choice (FOLFOX or FOLFIRI) in Part A or 2:1 in Part B to receive the recommended Part B dose or Physician's Choice. The stratification factors at randomization include geographic region, prior lines of chemotherapy (1 or ≥ 2) and Physician’s choice. Tinengotinib will be administered orally QD in 28-day cycles. Subjects will continue to receive study treatment until confirmed disease progression, unacceptable toxicity, withdrawal of consent, or termination of study by Sponsor, whichever occurs first. For Part A, the primary endpoint is safety/tolerability; secondary endpoints include objective response rate (ORR), duration of response (DOR) and PK analysis. For Part B, the primary endpoint is progression-free survival (PFS); secondary endpoints include overall survival (OS), ORR, DOR, safety, quality of life and population PK. Exploratory endpoints will assess the correlations between baseline FGFR2 alterations by cfDNA and efficacy, and exposure-response in terms of efficacy and safety. Study is open for enrollment. Clinical trial information: NCT05948475.