Role of immunotherapy in the management of hepatocellular carcinoma: current standards and future directions.

The multikinase inhibitor sorafenib was the only approved systemic therapy in advanced hepatocellular carcinoma (hcc) for about a decade. In recent years, the number of approved agents has increased significantly as a result of a number of positive phase iii clinical trials. Lenvatinib as a first-line treatment, and regorafenib, cabozantinib, and ramucirumab in the second-line setting are now approved by the U.S. Food and Drug Administration (fda) and the European Medicines Agency. In phase ii studies, immunotherapy with nivolumab and monotherapy using pembrolizumab yielded impressive results for overall survival in therapy-naïve and pretreated patients, leading to the accelerated approval by the fda of nivolumab and pembrolizumab for second-line treatment. However, phase iii trials of nivolumab in the first line and pembrolizumab in the second line as single agents failed to reach statistical significance, although clinical benefit for a subset of patients with long durations of response could be demonstrated. Despite that setback, immunotherapy for hcc is a promising therapeutic approach, and the combination of immunotherapy with other treatment modalities such as monoclonal antibodies, tyrosine kinase inhibitors, or local therapies has the potential to increase the overall response rate and survival. Recently, the results of a phase iii trial of combination atezolizumab-bevacizumab compared with sorafenib showed a highly significant survival benefit and median overall survival that was not reached in the immunotherapy arm, making the combination the preferred standard of care in first-line therapy. Despite the impressive results and generally good toxicity profile of immunotherapy, patients who respond to therapy constitute only a subset of the overall population, and response rates are still limited. This review focuses on the currently reported results and ongoing clinical trials of checkpoint inhibitor-based immunotherapy in hcc.