Unlike most solid tumors, incidence and mortality of hepatocellular carcinoma (HCC) have increased in the US and Europe in the last decade. Most patients are diagnosed at advanced stages, so there is an urgent need for new systemic therapies. Sorafenib, a tyrosine kinase inhibitor (TKI), has demonstrated clinical efficacy in patients with HCC. Studies in patients with lung, breast, or colorectal cancers indicated that the genetic heterogeneity of cancer cells within a tumor affect its response to therapeutics designed to target specific molecules. When tumor progression requires alterations in specific oncogenes (oncogene addiction), drugs that selectively block their products might slow tumor growth. However, no specific oncogene alterations are yet known to be implicated in HCC progression, so it is important to improve our understanding of its molecular pathogenesis.
There are currently many clinical trials evaluating TKIs for HCC, including those tested in combination with (e.g., erlotinib) or compared to (e.g., linifanib) sorafenib as a first-line therapy. For patients that do not respond or are intolerant to sorafenib, TKIs such as brivanib, everolimus, and monoclonal antibodies (e.g. ramucirumab) are being tested as second-line therapies. There are early-stage trials investigating the efficacy for up to 60 reagents for HCC. Together, these studies might change the management strategy for HCC, and combination therapies might be developed for patients with advanced HCC.
Identification of oncogenes that mediate progression of HCC, and trials that monitor their products as biomarkers, might lead to personalized therapy; reagents that interfere with signaling pathways required for HCC progression might be used to treat selected populations, and thereby maximize the efficacy and cost-benefit.