Multicenter phase 1b trial of cabozantinib plus atezolizumab for previously untreated aHCC and previously treated G/GEJ cancer

COSMIC-021 is a multicenter phase 1b trial of the combination of cabozantinib (multikinase inhibitor) and atezolizumab (anti-PD-L1) for solid tumors in adult patients. The expansion cohorts 14 and 15 evaluated this combination for previously untreated advanced hepatocellular carcinoma (aHCC) and previously treated gastric cancer or gastroesophageal junction adenocarcinoma (GC/GEJ), respectively. The primary endpoint was investigator-assessed objective response rate. The figure shows that the ORR was 13% (95% CI 4-31) in the aHCC cohort and 0% (0-11) in the GC/GEJ cohort. Twenty percent of aHCC patients and 10% of GC/GEJ patients had treatment-related adverse events resulting in discontinuation of either study drug. The authors conclude that the combination of cabozantinib and atezolizumab had clinical activity with a manageable safety profile in previously untreated aHCC patients.