Porter, Kyle M.

Background: Hepatocellular carcinoma (HCC) is a leading cause of cancer-related death in the United States and worldwide. HCC screening among patients at elevated risk is associated with improved early detection and overall survival, but current ultrasound-based screening strategies are challenged by low adherence and suboptimal sensitivity. Blood-based screening tests have the potential to enhance adherence and improve early-stage HCC detection if they can demonstrate favorable performance compared with ultrasound-based screening. Here we present the design and rationale for ALTUS (A lternative to Ultrasound), a prospective, longitudinal, multicenter study in the United States to investigate the performance of the multi-target HCC blood test (mt-HBT) for the detection of HCC in a screening population. Methods: Adults with liver cirrhosis or chronic hepatitis B infection will be enrolled to undergo standard-of-care screening imaging and concurrent blood collection for the mt-HBT. All participants will undergo contrast-enhanced CT or MRI imaging with central radiology LI-RADS assessment as the reference method to determine HCC status. Participants without an identified malignancy will undergo a second screening visit and blood collection, and longitudinal clinical and imaging data will be collected up to 18 months from enrollment. The primary study objectives are to demonstrate that the mt-HBT is non-inferior to ultrasound for early-stage HCC sensitivity and to assess mt-HBT HCC specificity. The secondary objective is to assess mt-HBT overall sensitivity. Results: ALTUS is in progress with readout of the primary analysis expected in 2025. Conclusions: This prospective head-to-head comparison of the mt-HBT versus ultrasound will provide novel data regarding the performance and utility of the mt-HBT for HCC screening.

TPS486 Background: Hepatocellular carcinoma (HCC) is a major cause of cancer-related death in the U.S. HCC surveillance is associated with improved early detection and receipt of curative treatment. However, current surveillance strategies suffer from low adherence and suboptimal sensitivity. The multi-target HCC blood test (mt-HBT) is a novel early detection assay that provides a qualitative result based on a multiparametric algorithm that incorporates information from methylation markers ( HOXA1, TSPYL5, and B3GALT6), AFP, and patient sex. Here, we describe the protocol for a prospective, multicenter clinical trial designed to investigate the performance of the mt-HBT in patients at risk for HCC. Methods: ALTernative to U/S (ALTUS) is a longitudinal, multicenter, prospective study with a targeted enrollment of 3,000 participants. The main inclusion and exclusion criteria are described in the table. Participants will receive HCC surveillance imaging (either U/S or CT/MRI) and blood collection for the mt-HBT. Those with positive U/S are anticipated to receive standard-of-care imaging follow-up with a multiphase CT or MRI, and those with a negative U/S will receive a study CT/MRI within 30 days of blood collection. Imaging interpretation is based on the CT/MRI LI-RADS (LR) v2018 categories. The primary endpoints are the overall sensitivity and specificity of the mt-HBT to detect HCC, defined as pathology-confirmed HCC or hepatocellular cholangiocarcinoma (cHCC-CCA), LR-4/5, or LR-TIV/M plus definite/probable HCC or cHCC-CCA. The secondary endpoints are mt-HBT early-stage sensitivity, and performance in a) participants with LR-5 or biopsy-confirmed HCC and b) participants confirmed non-HCC. Participants not diagnosed with a liver malignancy at visit one will continue to receive HCC surveillance, returning for a second visit ̃6 months from first blood collection. Blood will be collected after the second visit for the mt-HBT. Data on treatment will be collected for those diagnosed with HCC. Study participants and providers will be blinded to the mt-HBT results. Participants are currently enrolling across the U.S., with 60 targeted sites and an anticipated 12-month enrollment window. Clinical trial information: NCT05064553. [Table: see text]