On May 29, 2020, the FDA approved the combination of 2 immunotherapies, atezolizumab (Tecentriq; Genentech), a PD-L1 inhibitor, and bevacizumab (Avastin; Genentech), a vascular endothelial growth factor inhibitor, for the treatment of patients with unresectable or metastatic hepatocellular carcinoma (HCC) who have not received systemic therapy.
Atezolizumab and bevacizumab have each previously been approved as monotherapy or in combination with other therapies for multiple indications. This is their first indication for HCC, and this is the first immunotherapy regimen approved by the FDA for first-line treatment of unresectable or metastatic HCC. Sorafenib (Nexavar), a kinase inhibitor, is currently the standard of therapy for first-line treatment of unresectable or metastatic HCC. It is estimated that more than 42,000 Americans will be diagnosed with liver cancer in 2020. HCC accounts for approximately 75% of all liver cancer cases in the United States.
“The results of the IMbrave150 study are really transformative for patients with advanced liver cancer, one of the few cancers with a rising death rate and limited options in the first-line setting,” said Richard S. Finn, MD, Professor of Medicine, David Geffen School of Medicine, UCLA, and Director, Signal Transduction and Therapeutics Program, UCLA Jonsson Comprehensive Cancer Center. “For the first time we have a regimen that markedly improves survival over sorafenib, the standard of care for first-line hepatocellular carcinoma since 2007, and offers patients the opportunity for improved disease control with a favorable tolerability profile.”
The FDA approved atezolizumab and bevacizumab for advanced HCC based on results from the phase 3 IMbrave150 clinical trial, a multicenter, open-label study that included 501 patients with unresectable or metastatic HCC who had not received systemic therapy. Patients were randomized in a 2:1 ratio to a combination of intravenous (IV) atezolizumab 1200 mg administered on day 1 of each 21-day cycle, plus IV bevacizumab 15 mg/kg administered on day 1 of each 21-day cycle (N = 336), or to monotherapy with oral sorafenib 400 mg, taken twice daily on days 1 to 21 of each 21-day cycle.
The study’s primary end points were overall survival (OS) and progression-free survival (PFS) as evaluated by an independent review facility per Response Evaluation Criteria in Solid Tumors version 1.1. Patients received the combination immunotherapy or sorafenib (N = 165) until disease progression or unacceptable toxicity.
The combination of atezolizumab and bevacizumab improved OS by 42% (hazard ratio [HR], 0.58; 95% confidence interval [CI], 0.42-0.79; P = .001). The median PFS was 6.8 months (95% CI, 5.7-8.3) versus 4.3 months (95% CI, 4.0-5.6), for a reduction in PFS or death by 41% (HR, 0.59; 95% CI, 0.47-0.76; P <.0001) compared with sorafenib. At 12 months, the OS was 67.5% (95% CI, 61.3-73.1) with atezolizumab plus bevacizumab versus 54.6% (95% CI, 45.2-64) with sorafenib.
IMbrave150 is the first phase 3 immunotherapy study to show an improvement in OS and PFS in patients with unresectable or metastatic HCC compared with sorafenib.
The most common (≥2%) serious adverse reactions with the immunotherapy combination were gastrointestinal bleeding, infections, and fever.
Grade 3 or 4 adverse events occurred in 56.5% of those who received the immunotherapy combination and in 55.1% of the patients who received sorafenib. The rate of grade 3 or 4 hypertension was 15.2% with the immunotherapy combination.