in patients with hepatocellular carcinoma, shows a new study.
While the combination has been shown to be beneficial in renal cell carcinoma and other solid tumor types, it has never before been tested in a phase 3 clinical trial for hepatocellular carcinoma until now.
The new study, published in The Lancet Oncology, included 837 patients from 178 hospital in 32 countries who were enrolled in the study (called COSMIC-312) between December 2018 and August 2020. 432 patients were randomly assigned to receive a combination of cabozantinib (Cabometyx, Exelixis), a tyrosine kinase inhibitor (TKI), and atezolizumab (Tecentriq, Genentech), a PD-L1 inhibitor. While 217 patients were treated with sorafenib (Nexavar, Bayer) alone and 188 patients were treated with cabozantinib.
Clinically meaningful improvements in progression-free survival, increased disease control and lower primary progression were seen in patients who received the cabozantinib and atezolizumab combination therapy over patients who were treated with sorafenib. However, there was no improvement in overall survival.
“The improvement in progression-free survival with cabozantinib plus atezolizumab in this study shows that the combination confers clinical benefit for patients with advanced hepatocellular carcinoma previously untreated with systemic anticancer therapy,” wrote the authors of the study, led by Robin Kate Kelley, MD, a gastrointestinal oncologist with the University of California, San Francisco, and Lorenza Rimassa, MD, a gastrointestinal oncologist with Humanitas University, Milan. “The absence of a benefit in overall survival, along with the availability of atezolizumab in combination with bevacizumab, indicates the need for additional studies to determine if cabozantinib plus atezolizumab would be an appropriate first-line treatment option in select patient populations.”
For symptomatic patients with high disease burden or main portal vein occlusion who are at risk for impending complications, controlling the disease as quickly as possible is vital, the authors wrote. “Underlying chronic liver disease is nearly universal in patients with hepatocellular carcinoma and the risk of gastrointestinal bleeding is high in this population, particularly if portal vein tumor thrombus is present.”
Hepatocellular carcinoma (HCC) is an angiogenic tumor, making it a logical target for TKIs that target vascular endothelial growth factor. The TKI sorafenib was the first to be approved as a first-line treatment for HCC, and since then immune checkpoint inhibitors have been shown to induce durable responses in the first-line setting, but have not improved overall survival in randomized trials.
Study methodology
In the study, after a median follow-up of 15.8 months, median progression-free survival was 6.8 months in the combination group and 4.2 months in the sorafenib group (hazard ratio, 0.63; P = .0012). The median overall survival was 15.4 months in the combination group and 15.5 months in the sorafenib group (not significant). Grade 3-4 adverse events included an increase in ALT, which occurred in 9% of the combination group, 3% of the sorafenib group, and 6% of the cabozantinib only group; hypertension (9%, 8%, and 12%, respectively); an increase in AST increase (9%, 4%, 10%); and palmar-plantar erythrodysesthesia (8%, 8%, 9%). Serious treatment-related adverse events occurred in 18% of patients in the combination arm, 8% in the sorafenib arm, and 13% in the cabozantinib arm.
There were no excess serious bleeding events in the treatment groups containing cabozantinib, compared with sorafenib which is noteworthy because HCC patients are at high risk for gastrointestinal bleeding.
Treatment-related grade 5 events were rare, occurring in 1% (six patients) of the combination group, and in just one patient in both the sorafenib and cabozantinib groups.
Although the results suggest promising clinical benefit, the lack of overall survival benefit limit the implications of these findings. Since atezolizumab combined with bevacizumab is also available for this patient population, more research is needed to determine if cabozantinib plus atezolizumab can become a first-line option.
The study had some limitations: Participants had to have a Child-Pugh class of A, though there was no requirement to assess for fibrosis or cirrhosis. Otherwise there were few barriers to study entry.
The study was sponsored by Exelixis (Alameda) and Ipsen (Boulogne-Billancourt, France).