Background: Hepatocellular carcinoma (HCC) is the 4th leading cause of cancer related death worldwide. HCC typically develops in patients with cirrhosis and has a 5-year survival estimate of 20%. Only patients with early stage disease may be eligible for a curative approach using local treatment and/or transplant. The majority of patient present with advanced HCC and will require systemic treatment for disease control. Several systemic therapies are FDA-approved for the treatment of HCC; however, they are only approved for patients with Child-Pugh class A cirrhosis. There are limited data and no approved second-line therapy for HCC with more advanced cirrhosis, including Child-Pugh class B, which represents a significant proportion of patients. The aim of this trial is to determine the safety and efficacy of cabozantinib, a multi-kinase inhibitor, in patients with HCC with Child-Pugh class B cirrhosis. Methods: This investigator-initiated, phase I/II study is enrolling 32 patients with advanced HCC, Child-Pugh B7 or B8, who have previously received first-line systemic treatment. Patients receive cabozantinib at one of 3 dose levels (20 mg, 40 mg, and 60 mg) with a starting dose level of 40 mg to evaluate the safety profile and obtain the recommended phase 2 dose (RP2D). The primary endpoint is assessment of dose-limiting toxicity with a null hypothesis greater than 35%. Secondary endpoints include ORR per RECIST v1.1, PFS, OS, and PK profile. Exploratory endpoints include whole exome/RNAseq analysis (including MET, VEGF, AXL, and immune signature), spatial profiling of immune markers by multiplex immunofluorescence, and specimen banking (tissue, blood and imaging). The trial design is based on the Time-To-Event modification of the Continual Reassessment Method (TiTE-CRM), which allows for continued monitoring of toxicity as a function of a dose-over-time, and is flexible with regard to the number of patients treated at a certain dose. The trial is open at University of Michigan as lead and coordinating site, and due to open at 3 additional high-volume centers. Clinical trial information: 04497038.