Exelixis, Inc. announced detailed results from the first planned analysis of COSMIC-312, the ongoing phase 3 pivotal trial evaluating cabozantinib (CABOMETYX?) in combination with atezolizumab versus sorafenib in patients with previously untreated advanced hepatocellular carcinoma (HCC). New results presented during the 2021 ESMO Virtual Plenary include detailed data for a prespecified interim analysis for the primary endpoint of overall survival (OS) in the intent-to-treat (ITT) population, which was conducted at the same time as the primary analysis for PFS in the PITT population. At a median follow-up of 13.6 months, the interim OS analysis in the ITT population showed a trend that favored cabozantinib in combination with atezolizumab but did not reach statistical significance (HR: 0.90; 96% CI: 0.69-1.18; P=0.438). Median OS was 15.4 months for cabozantinib in combination with atezolizumab (n=432) versus 15.5 months for sorafenib (n=217). The trial is continuing as planned to the final analysis of OS, anticipated in early 2022. In an interim analysis of the secondary endpoint of PFS per RECIST 1.1 by BIRC performed to determine the contribution of cabozantinib to the combination with atezolizumab, cabozantinib monotherapy reduced the risk of disease progression or death in the ITT population by 29% versus sorafenib (HR: 0.71; 99% CI: 0.51-1.01; P=0.0107; pre-specified critical p-value of 0.00451). Median PFS was 5.8 months for cabozantinib (n=188) versus 4.3 months for sorafenib (n=217). Objective response rates per RECIST 1.1 by BIRC in the ITT population were 11% for cabozantinib in combination with atezolizumab, 3.7% for sorafenib and 6.4% for cabozantinib monotherapy. Disease control rates (complete response + partial response + stable disease) were 78%, 65% and 84%, respectively.