Adjuvant Atezolizumab plus Bevacizumab vs. Active Surveillance for HCC

Combination therapy with immune checkpoint inhibitors is first line treatment for unresectable or metastatic hepatocellular carcinoma (HCC). After resection or ablation of HCC, there is no proven benefit for adjuvant therapy. Investigators now report interim results from IMbrave50, an open-label, international, industry-sponsored, phase 3 trial evaluating adjuvant treatment with atezolizumab plus bevacizumab in patients with HCC and high risk for recurrence after resection or ablation.

Patients with Child-Pugh class A liver function who had undergone R0 resection or microwave or radiofrequency ablation with complete response were randomized to either active surveillance or one year of treatment with atezolizumab (1200 mg) and bevacizumab (15 mg/kg) every 3 weeks. Most of the 668 patients were male (83%), were Asian (82%), had hepatitis B as the risk factor (62%), underwent surgical resection (88%), and had a solitary tumor (88%). The median diameter of the largest tumor was 5.5 cm among patients who underwent resection and 2.5 cm among those who underwent ablation.

At a median follow-up of 17 months, the primary endpoint of centrally assessed relapse-free survival was superior for atezolizumab/bevacizumab compared to active surveillance (78% vs. 65%; hazard ratio, 0.72; P=0.012). Median relapse-free survival was not reached in either group. The majority of recurrences in both the atezolizumab/bevacizumab and active surveillance groups were intrahepatic (67% and 66%). Overall survival results had not matured at the time of the analysis, and crossover to atezolizumab/bevacizumab was permitted at disease progression. Adverse events leading to atezolizumab/bevacizumab discontinuation occurred in 9% of patients.