Atezolizumab plus Bevacizumab versus Sorafenib in the Chinese Subpopulation with Unresectable Hepatocellular Carcinoma: Phase 3 Randomized, Open-Label IMbrave150 Study

Introduction: Atezolizumab plus bevacizumab significantly improved overall survival (OS) and progression-free survival (PFS) versus sorafenib in patients with unresectable hepatocellular carcinoma (HCC) in IMbrave150. Efficacy and safety data from the Chinese subpopulation are reported. Methods: IMbrave150, a global, randomized, open-label, phase 3 study in patients with systemic treatment-naive unresectable HCC, included an extension phase that enrolled additional patients from mainland China. Patients were randomized (2:1) to receive intravenous atezolizumab 1,200 mg plus bevacizumab 15 mg/kg once every 3 weeks or sorafenib 400 mg twice a day until unacceptable toxicity or loss of clinical benefit. Co-primary endpoints were OS and independent review facility-assessed PFS per Response Evaluation Criteria in Solid Tumors version 1.1 in the intention-to-treat population. Results: Of 194 Chinese patients enrolled from April 16, 2018, to April 8, 2019 (137 in the global study and 57 in the China extension phase), 133 received atezolizumab plus bevacizumab and 61 received sorafenib. At the data cutoff (August 29, 2019), the stratified hazard ratio for OS was 0.44 (95% CI, 0.25-0.76) and for PFS was 0.60 (95% CI, 0.40-0.90). The respective median OS and PFS with atezolizumab plus bevacizumab were not reached (NR; 95% CI, 13.5 months to NR) and 5.7 months (95% CI, 4.2-8.3) versus 11.4 months (95% CI, 6.7 to NR) and 3.2 months (95% CI, 2.6-4.8) with sorafenib. Grade 3-4 adverse events (AEs) occurred in 78 of 132 (59.1%) atezolizumab plus bevacizumab-treated and 27 of 58 (46.6%) sorafenib-treated patients. The most common grade 3-4 AE with atezolizumab plus bevacizumab was hypertension, occurring in 15.2% of patients; however, other high-grade AEs were infrequent. Conclusion: Clinically meaningful improvements in OS and PFS observed with atezolizumab plus bevacizumab versus sorafenib suggest that atezolizumab plus bevacizumab may become a practice-changing treatment for Chinese patients with unresectable HCC.

Automated summary

The study demonstrates that atezolizumab plus bevacizumab significantly improves overall survival and progression-free survival in Chinese patients with unresectable hepatocellular carcinoma compared to sorafenib, with hypertension being the most common grade 3-4 adverse event and other high-grade adverse events being infrequent.