Molecularly targeted therapy for advanced gastrointestinal noncolorectal cancer treatment: how to choose? Past, present, future

Gastrointestinal cancer is a leading cause of death worldwide. Conventional cytotoxic chemotherapy has been the backbone of advanced gastrointestinal cancer treatment for decades and still represents a key element of the therapeutic armamentarium. However, only small increments in survival outcomes have been reached. New clinical trials are designed, including classic chemotherapy in association with either small-molecule inhibitors or mAb. During the past few years, remarkable progress in molecular biology of gastrointestinal noncolorectal cancers, the discovery of specific targets and the resulting development of systemic drugs that block critical kinases and several molecular pathways have all contributed to progress. New biological agents with molecularly targeted therapies are now available or currently included in clinical trials (EGFR inhibitors (i), antiangiogenic agents, c-METi, IDHi, FGFR2i, BRAFi, Pi3Ki/AKTi/mTORi, NTRKi). When we focus on the current state of precision medicine for gastrointestinal malignancies, it becomes apparent that there is a mixed history of success and failure. The aim of this review is to focus on the studies that have been completed to date with target therapies and to understand which of these are currently the accepted choice in clinical practice and which need further confirmation and approval for inclusion in guidelines. All these findings will enable to guide clinical practice for oncologists in the design of the next round of clinical trials.

Targeted agents and systemic therapy in hepatocellular carcinoma

Cytotoxic chemotherapy, hormonal agents, and immunotherapy have been tested in hepatocellular cancer (HCC) with marginal efficacy to date. Recent insights into the molecular pathogenesis of HCC have identified several aberrant signaling pathways that have served as targets for novel therapeutic agents. These discoveries have been translated into the clinical realm with the use of the antiangiogenic and the Raf kinase inhibitor, sorafenib, and have revealed the potential of targeted agents to produce clinically meaningful survival benefits in patients with advanced HCC. Efforts continue in the quest to improve the outcome of HCC patients through the development and evaluation of other targeted agents, and to better understand the interactions between the underlying disease biology and response to therapy. Several pathways are now implicated in hepatocarcinogenesis and agents that target these pathways continue to be developed.

Phase II study of bevacizumab and erlotinib in the treatment of advanced hepatocellular carcinoma patients with sorafenib-refractory disease

Background The combination of bevacizumab (B) and erlotinib (E) has shown promising clinical outcomes as the first-line treatment of advanced HCC patients. We aimed to evaluate the efficacy and safety of using combination of B + E in treating advanced HCC patients who had failed prior sorafenib treatment. Methods Eligible advanced HCC patients with documented radiological evidence of disease progression with sorafenib treatment were recruited. All patients received bevacizumab(B) at 10 mg/kg every 2 weeks with erlotinib(E) at 150 mg daily for a maximum of 6 cycles. Response assessments using both RECIST and modified RECIST criteria were performed after every 6 weeks. The primary endpoint was clinical benefit (CB) rate and a Simon two-stage design was employed. Results The trial was halted in the first stage according to the pre-set statistical criteria with 10 patients recruited. The median age was 47 years (range, 28–61) and all patients were in ECOG performance status 1. Eighty percent of patients were chronic hepatitis B carriers and all patients had Child A cirrhosis. Among these 10 patients, none of the enrolled patients achieved response or stable disease. The median time-to-progression was 1.81 months (95 % confidence interval [C.I.], 1.08–1.74 months) and overall survival was 4.37 months (95 % C.I., 1.08–11.66 months). Rash (70 %), diarrhea (50 %) and malaise (40 %) were the most commonly encountered toxicities. Conclusion The combination of B + E was well tolerated but had no activity in an unselected sorafenib-refractory advanced HCC population. Condensed abstract The combination of bevacizumab and erlotinib had no clinical activity in sorafenib-refractory HCC population.

HCC and angiogenesis: possible targets and future directions

Hepatocellular carcinoma (HCC), the most common primary liver tumor, is notoriously resistant to systemic therapies, and often recurs even after aggressive local therapies. HCCs rely on the formation of new blood vessels for growth, and VEGF is critical in this process. A hallmark of new vessel formation in tumors is their structural and functional abnormality. This leads to an abnormal tumor microenvironment characterized by low oxygen tension. The liver is perfused by both arterial and venous blood and the resulting abnormal microenvironment selects for more-aggressive malignancies. Anti-VEGF therapy with sorafenib was the first systemic therapy to demonstrate improved survival in patients with advanced-stage HCC. This important development in the treatment of HCC raises hope as well as critical questions on the future development of targeted agents including other antiangiogenic agents, which hold promise to further increase survival in this aggressive disease.

[New possibilities of targeted therapy in the treatment of hepatocellular carcinoma with the help of molecular biology]

Hepatocellular carcinoma (HCC) has a poor prognosis. Approximately 85% of patients are not candidates for curative treatments at the time of diagnosis; hence palliative modalities (transcatheter arterial chemoembolisation, radiofrequency ablation, systemic chemotherapy) are used. Systemic chemotherapies have disappointing results. The increasing knowledge in the molecular biology of HCC will increase the possibilities of targeted therapy. The multi-tyrosine kinase inhibitor sorafenib is the only drug which has approved. The VEGF-inhibitors (bevacizumab, sunitinib), EGFR-blocker agents (erlotinib), as well as the inhibition of mTOR (rapamycin) are promising. Combination of sorafenib or other anti-angiogenic agents with local ablative procedure (transcatheter arterial chemoembolisation, radiofrequency ablation), or with curative hepatectomy also can be favorable. Alteration of Wnt pathway, retinoid compounds, inhibition of the cell cycle as well as the proteosome, and epigenetic therapy can be other potential promising targets in HCC.

Advanced hepatocellular carcinoma: early evaluation of response to bevacizumab therapy at dynamic contrast-enhanced US with quantification--preliminary results

PURPOSE

To investigate whether there is any correlation between standard efficacy endpoints-specifically, tumor response, progression-free survival, and overall survival-and tumor perfusion parameters measured by using dynamic contrast material-enhanced ultrasonography (US) in patients with advanced hepatocellular carcinoma (HCC) treated with bevacizumab.

MATERIALS AND METHODS

The institutional review board approved the study, and all patients provided written informed consent before their enrollment. Between June 3, 2005, and September 28, 2007, 42 patients (33 men, nine women; median age, 62 years; age range, 23-84 years) participated in this phase II study of single-agent bevacizumab treatment. Tumor response (based on RECIST [response evaluation criteria in solid tumors]) at 2 months was assessed in 37 patients, and progression-free survival and overall survival were assessed in all 42 patients. Dynamic contrast-enhanced US (ie, dynamic US) was performed before treatment (day 0); on days 3, 7, 14, and 60 after treatment; and every 2 months thereafter. Tumor perfusion parameters were estimated quantitatively from contrast material uptake curves constructed from raw linear data. The changes in dynamic US functional parameters between day 0 and the later time points were compared between treatment responders and nonresponders by using nonparametric tests. Given multiple comparisons, P < .001 indicated significance.

RESULTS

The percentage decrease in several dynamic US parameters between day 0 and day 3 showed trends toward correlation with (a) tumor response in terms of total area under the time-intensity curve (AUC) (P = .02), AUC during wash in (P = .04), AUC during washout (P = .02), and time to peak intensity (P = .03); (b) progression-free survival in terms of time to peak intensity (P = .028); and (c) overall survival in terms of AUC (P = .002) and AUC during washout (P = .003).

CONCLUSION

Dynamic US can be used to quantify dynamic changes in tumor vascularity as early as 3 days after bevacizumab administration in patients with HCC. These early changes in tumor perfusion may be predictive of tumor response at 2 months, progression-free survival, and overall survival, and they may be potential surrogate measures of the effectiveness of antiangiogenic therapy in patients with HCC.

Developing better treatments in hepatocellular carcinoma

The marked heterogeneity of hepatocellular carcinoma (HCC), particularly with regard to the etiology and severity of the underlying cirrhosis, makes clinical trial design in this disease very challenging. In addition, despite the global burden of HCC, there have been relatively few randomized studies. The major advance in medical therapy in HCC has been the benefit of sorafenib, as demonstrated in two Phase III studies. However, the benefit is small, and new therapies to augment or replace sorafenib are urgently needed. These newer therapies, as well as the progress made in two important areas – clinical trial design and molecular characterization – are the subject of this article.

Beyond sorafenib: novel targeted therapies for advanced hepatocellular carcinoma

IMPORTANCE OF THE FIELD

The successful approval of sorafenib has greatly stimulated the development of other molecular targeted agents in advanced hepatocellular carcinoma (HCC).

AREAS COVERED IN THIS REVIEW

The aim of this review was to summarize the key data of sorafenib Phase III studies and the lessons and unanswered questions with sorafenib in HCC. It extensively updated the current ongoing studies combining sorafenib with erlotinib and other targeted agents or chemotherapy, and many molecularly targeted agents under development that inhibit angiogenesis, EGFR, and mammalian target of rapamycin (mTOR).

WHAT THE READER WILL GAIN

A comprehensive understanding of the current status of drug development of targeted agents in advanced HCC and insights into the challenges of developing these agents in HCC.

TAKE HOME MESSAGE

Sorafenib is the first and only approved agent in advanced HCC. Several Phase III studies are ongoing with other drugs in advanced HCC. Many early clinical trials are conducted to assess other molecularly targeted agents that inhibit different pathways of hepatocarcinogenesis.

The present and the future landscape of treatment of advanced hepatocellular carcinoma

Hepatocellular carcinoma (HCC) is a highly lethal disease that is resistant to conventional cytotoxic drugs. Historically, effective systemic treatment options have not been available for patients with unresectable advanced disease. However, an improved understanding of the molecular mechanisms that regulate tumor initiation and progression over the past few years has led to the development of novel molecularly-targeted therapies that specifically block the different cellular signaling pathways involved. Recently, the antiangiogenesis and Raf kinase inhibitor, sorafenib showed a survival advantage in advanced stage HCC in two randomized, double-blind, controlled trials. These positive results were the first to demonstrate the efficacy of molecularly-targeted therapies in advanced HCC. Moreover, results from phase I and II trials evaluating other agents in this disease are promising and are under active clinical development. In the near future, we expect to have more data, knowledge, and evidence regarding the use of molecularly-targeted therapies in advanced HCC, both as single agents and in combination regimens. In this review, we will summarize the data concerning the present standard treatment for advanced HCC and discuss the newest, most promising clinical research that may affect the future treatment of this disease.

Nonoperative therapies for combined modality treatment of hepatocellular cancer: expert consensus statement

Although surgical resection and liver transplantation are the only treatment modalities that enable prolonged survival in patients with hepatocellular carcinoma (HCC), the majority of HCC patients presents with advanced disease and do not undergo resective or ablative therapy. Transarterial chemoembolization (TACE) is indicated in intermediate/advanced stage unresectable HCC even in the setting of portal vein involvement (excluding main portal vein). Sorafenib has been shown to improve survival of patients with advanced HCC in two controlled randomized trials. Yttrium 90 is a safe microembolization treatment that can be used as an alternative to TACE in patients with advanced liver only disease or in case of portal vein thrombosis. External beam radiation can be helpful to provide local control in selected unresectable HCC. These different treatment modalities may be combined in the treatment strategy of HCC and also used as a bridge to resection or liver transplantation. Patients should undergo formal multidisciplinary evaluation prior to initiating any such treatment in order to individualize the best available options.

Systemic treatment of hepatocellular carcinoma: dawn of a new era?

PURPOSE AND DESIGN

Despite decades of efforts by many investigators, systemic chemotherapy or hormone therapy have failed to demonstrate improved survival in patients with advanced hepatocellular carcinoma (HCC). On the basis of placebo-controlled, randomized phase III trials, sorafenib has shown improved survival benefits in advanced HCC and has set a new standard for future clinical trials. The successful clinical development of sorafenib in HCC has ushered in the era of molecularly targeted agents in this disease, which is discussed in this educational review.

RESULTS AND CONCLUSION

Ongoing studies are evaluating the efficacy and tolerability of combining sorafenib with erlotinib and other targeted agents or chemotherapy. Many molecularly targeted agents that inhibit angiogenesis, epidermal growth factor receptor, and mammalian target of rapamycin are at different stages of clinical development in advanced HCC. Combining targeted agents that inhibit different pathways in hepatocarcinogenesis is an area of active investigation. Future research should continue to unravel the mechanism of hepatocarcinogenesis and to identify key relevant molecular targets for therapeutic intervention. Identification and validation of potential surrogate and predictive biomarkers holds promise to individualize patients' treatment to maximize clinical benefit and minimize the toxicity and cost of targeted agents. We hope that we will continue to improve the efficacy of systemic therapy in advanced HCC in the coming years.

[Targeted therapies in hepatocellular carcinoma]

Hepatocellular carcinoma (HCC) stands as a major health problem worldwide. The management of advanced HCC, limited for a longtime by the disappointing results of conventional cytotoxic chemotherapies, has recently changed with the publication of the results of the Sorafenib Hepatocellular Carcinoma Assessment Randomized Protocol (SHARP) trial, which demonstrated an overall survival benefit over placebo in patients with advanced HCC. This study was further confirmed by the Asian-Pacific trial using sorafenib in Eastern patients. Those trials demonstrated that therapeutic benefits may derive from improving our knowledge of deregulated signaling pathways involved in HCC carcinogenesis. This review summarizes the results of clinical trials in which targeted therapies are currently evaluated aiming to enlarge the therapeutic armamentarium for HCC in a near future.

Medical treatment of unresectable hepatocellular carcinoma: Going beyond sorafenib

Even though Sorafenib has radically changed the natural history of those hepatocellular carcinoma patients who are not amenable for curative treatments, further therapeutic improvements are badly needed. As it was for Sorafenib, our increasingly refined understanding of the complex mechanisms underlying HCC carcinogenesis are the starting point for the future development of such treatments. Presently, a number of molecularly targeted agents are in different stages of development for this once orphan cancer. Indeed, several pathways are presently being explored to identify potentially active drugs, including epidermal growth factor receptor, vascular endothelial growth factor/vascular endothelial growth factor receptors, mammalian target of rapamycin, phosphatidyl-inositol-3-kinase/Akt, insulin growth factor, Aurora kinase, Wnt/β-catenin, retinoic acid receptor and hepatocyte growth factor/C-Met. This review is aimed at addressing the results obtained so far with these newer drugs, also considering the challenges we shall face in the near future, including the issue of response evaluation and identification of predictive/prognostic biomarkers.

Efficacy and tolerability of bevacizumab plus capecitabine as first-line therapy in patients with advanced hepatocellular carcinoma

Background:

Molecularly targeted agents with anti-angiogenic activity, including bevacizumab, have demonstrated clinical activity in patients with advanced/metastatic hepatocellular carcinoma (HCC). This multicentre phase II study involving patients from several Asian countries sought to evaluate the safety and efficacy of bevacizumab plus capecitabine in this population.

Methods:

Histologically proven/clinically diagnosed advanced HCC patients received bevacizumab 7.5 mg kg^–1 on day 1 and capecitabine 800 mg m^–2 twice daily on days 1–14 every 3 weeks as first-line therapy.

Results:

A total of 45 patients were enrolled; 44 (96%) had extrahepatic metastasis and/or major vessel invasion and 30 (67%) had hepatitis B. No grade 3/4 haematological toxicity occurred. Treatment-related grade 3/4 non-haematological toxicities included diarrhoea (n=2, 4%), nausea/vomiting (n=1, 2%), gastrointestinal bleeding (n=4, 9%) and hand–foot syndrome (n=4, 9%). The overall response rate (RECIST) was 9% and the disease control rate was 52%. Overall, median progression-free survival (PFS) and overall survival (OS) were 2.7 and 5.9 months, respectively. Median PFS and OS were 3.6 and 8.2 months, respectively, for Cancer of the Liver Italian Programme (CLIP) score ⩽3 patients, and 1.4 and 3.3 months, respectively, for CLIP score 4 patients.

Conclusion:

The bevacizumab–capecitabine combination shows good tolerability and modest anti-tumour activity in patients with advanced HCC.

Vascular endothelial growth factor in the management of hepatocellular carcinoma: a review of literature

The importance of tumor angiogenesis in tumor biology is now widely accepted. Hepatocellular carcinoma (HCC) is a highly vascular tumor, and angiogenesis is believed to play a considerable role in its development and progression. The authors reviewed the role of circulating vascular endothelial growth factor (VEGF) in screening for HCC and in risk stratification and treatment monitoring. They searched the world medical literature by accessing MEDLINE and PubMed for articles on: 1) the utility of circulating VEGF for HCC screening in patients with cirrhosis; 2) the role of circulating VEGF as a predictor of the invasive potential of HCC; and 3) monitoring anti-HCC treatment effects by serial measurements of circulating VEGF. They found evidence to support a potential role for VEGF in screening and surveillance of HCC. They also found support for developing the use of VEGF in the monitoring of treatment outcomes. Several studies suggested that the circulating VEGF level may be an independent prognostic marker in HCC. Further studies are needed to determine the utility of circulating VEGF in screening of patients with cirrhosis and to determine its potential role as a prognostic and predictive biomarker in patients with HCC. Cancer 2009. (c) 2009 American Cancer Society.

Targeting angiogenesis in hepatocellular carcinoma: focus on VEGF and bevacizumab

Hepatocellular carcinoma (HCC) is one of the most common malignancies worldwide and one of the few malignancies with an increasing incidence in the USA. While the relationship between HCC and its inciting risk factors (e.g., hepatitis B, hepatitis C and alcohol liver disease) is well defined, driving genetic alterations are still yet to be identified. Clinically, HCC tends to be hypervascular and, for that reason, transarterial chemoembolization has proven to be effective in managing many patients with localized disease. More recently, angiogenesis has been targeted effectively with pharmacologic strategies, including monoclonal antibodies against VEGF and the VEGF receptor, as well as small-molecule kinase inhibitors of the VEGF receptor. Targeting angiogenesis with these approaches has been validated in several different solid tumors since the initial approval of bevacizumab for advanced colon cancer in 2004. In HCC, only sorafenib has been shown to extend survival in patients with advanced HCC and has opened the door for other anti-angiogenic strategies. Here, we will review the data supporting the targeting of the VEGF axis in HCC and the preclinical and early clinical development of bevacizumab.

Targeted therapy for hepatocellular carcinoma

Hepatocellular carcinoma (HCC) is one of the most common malignant tumors worldwide. The major etiologies and risk factors for development of HCC are well defined and some steps of hepatocellular carcinogenesis have been elucidated. Despite these scientific advances and the implementation of measures for early detection of HCC in patients who are at risk of this disease, survival of patients has not improved greatly over the past three decades. This situation is partly due to the limited therapeutic options available. While surgery and percutaneous or transarterial interventions are effective for patients with limited or compensated underlying liver disease, more than 80% of patients present with multifocal HCC and/or advanced liver disease, or have comorbidities at the time of diagnosis. Treatment options for these patients have previously been limited to best supportive care. The effectiveness of targeted therapy with monoclonal antibodies or small-molecule kinase inhibitors has now been demonstrated for the treatment of different tumors. In 2007, the multitargeted kinase inhibitor, sorafenib, was found to prolong survival significantly for patients with advanced HCC. This Review discusses the mechanisms of targeted therapies and clinical studies that have investigated these therapies in patients with HCC. Perspectives for future developments are also provided.

Molecular targeted therapy for hepatocellular carcinoma

A majority of patients with HCC present with advanced disease and are not candidates for liver transplantation, surgical resection, or regional therapy. Systemic cytotoxic chemotherapy agents are minimally effective, can have significant toxicity, and have not been shown to improve patient survival. Hepatocellular carcinomas are inherently chemotherapy-resistant tumors and are known to overexpress the multidrug resistance genes. Hepatocellular carcinoma is a very heterogeneous disease in terms of its etiology, molecular carcinogenic mechanisms, and biological behavior, which complicate our ability to identify rational molecular therapeutic "targets." Nearly every pathway involved in carcinogenesis is altered to some degree in HCC. Changes in hepatocyte growth factor expression, intracellular signaling, protease and matrix metalloproteinase expression, and oncogene expression are seen in HCC. The recent demonstration, in randomized clinical trials, of survival benefit for HCC patients treated with the oral agent sorafenib is encouraging progress in the development of molecularly targeted anticancer agents in HCC.

Molecular therapy for the treatment of hepatocellular carcinoma

Hepatocellular carcinoma (HCC) is the fifth most common cancer worldwide. Conventional cytotoxic chemotherapy has failed to show a substantial benefit for patients with HCC. Recently, a number of new drugs targeting molecular mechanisms involved in liver cell transformation have entered into clinical trials and led to encouraging results. In this review we summarise this data and point to a number of new compounds, which are currently being tested and can potentially broaden our therapeutic arsenal even further.

The impact of new data in the treatment of advanced hepatocellular carcinoma

Hepatocellular carcinoma (HCC) is the fifth most common cancer worldwide, causing 500,000 deaths yearly. The risk factors mostly responsible for the rising incidence of HCC in the Western hemisphere are hepatitis C, alcoholic cirrhosis, and nonalcoholic steatohepatitis, which most commonly leads to HCC in the setting of cirrhosis. Over the past 30 years, several chemotherapeutic single agents and combinations have been tested in HCC, yet none have demonstrated any improvement in survival. Recently, the multitargeted anti-angiogenic and Raf kinase inhibitor sorafenib has shown a survival advantage as a single agent and improved outcomes in combination with doxorubicin. Other novel agents have also shown intriguing outcomes as single agents (sunitinib) or in combination (bevacizumab and erlotinib). The encouraging results and clinical information gathered in recent trials are generating important clinical questions regarding which patients to treat, how to accommodate concurrent cirrhosis, and which parameters to use to monitor efficacy and the potential benefit from therapy.

Molecular targeted therapies in hepatocellular carcinoma

Hepatocellular carcinoma (HCC) is a complex and heterogeneous tumor with several genomic alterations. There is evidence of aberrant activation of several signaling cascades such as epidermal growth factor receptor (EGFR), Ras/extracellular signal-regulated kinase, phosphoinositol 3-kinase/mammalian target of rapamycin (mTOR), hepatocyte growth factor/mesenchymal-epithelial transition factor, Wnt, Hedgehog, and apoptotic signaling. Recently a multikinase inhibitor, sorafenib, has shown survival benefits in patients with advanced HCC. This advancement represents a breakthrough in the treatment of this complex disease and proves that molecular therapies can be effective in HCC. It is becoming apparent, however, that to overcome the complexity of genomic aberrations in HCC, combination therapies will be critical. Phase II studies have tested drugs blocking EGFR, vascular endothelial growth factor/platelet-derived growth factor receptor, and mTOR signaling. No relevant data has been produced so far in combination therapies. Future research is expected to identify new compounds to block important undruggable pathways, such as Wnt signaling, and to identify new oncogenes as targets for therapies through novel high-throughput technologies. Recent guidelines have established a new frame for the design of clinical trials in HCC. Randomized phase II trials with a time-to-progression endpoint are proposed as pivotal for capturing benefits from novel drugs. Survival remains the main endpoint to measure effectiveness in phase III studies. Patients assigned to the control arm should receive standard-of-care therapy, that is, chemoembolization for patients with intermediate-stage disease and sorafenib for patients with advanced-stage disease. Biomarkers and molecular imaging should be part of the trials, in order to optimize the enrichment of study populations and identify drug responders. Ultimately, a molecular classification of HCC based on genome-wide investigations and identification of patient subclasses according to drug responsiveness will lead to a more personalized medicine.

Systemic therapy for hepatocellular carcinoma

Hepatocellular carcinoma (HCC) is currently the fifth most common solid tumor worldwide and the third leading cause of cancer-related death. Eighty percent of new cases occur in developing countries, but the incidence is rising in economically developed regions including Japan, Western Europe, and the United States. More than 80% of patients present with advanced or unresectable disease, and for those patients who do undergo resection, the recurrence rates can be as high as 50% at 2 years. Thus, a large number of patients will seek systemic therapy. Systemic cytotoxic chemotherapy is largely ineffective and can have significant toxicity in patients with underlying liver dysfunction. Newer biologic agents that target molecular abnormalities common to HCC may improve the clinical outcome in patients with HCC.

Growth factors as therapeutic targets in HCC

Despite various effective local treatments for hepatocellular carcinoma (HCC), some patients do not meet the treatment criteria because of extrahepatic metastases or macroscopic vascular invasion at the time of their diagnosis. Furthermore, many patients treated with successful local treatments develop recurrences after treatment. Although these patients receive systemic treatment including chemotherapy, HCC is generally recognized as a chemo-resistant tumor. Recently, new molecular targets have been confirmed and various targeted agents are now being investigated for the treatment of HCC. Epidermal growth factor receptor (EGFR) is frequently expressed in human hepatoma cells, and EGF may be one of the mitogens that are needed for the growth of hepatoma cells. HCC is generally hypervascular, and vascular endothelial growth factor (VEGF) promotes HCC development and metastasis. Various inhibitors targeting EGFR and/or VEGF, VEGF receptor (VEGFR) have been developed as treatments of HCC. In phase-II studies of these growth factor inhibitors, the response rates are relatively low; however, high rates of disease control, enabling a good time to progression, have been achieved. Recently, a randomized phase III trial of sorafenib versus placebo conducted in patients with advanced HCC demonstrated the beneficial effects of this drug on the time-to-progression and overall survival of the patients, and the drug could become established as the standard chemotherapeutic agent for advanced HCC. Further clinical trials using biologic agents are warranted to prolong the survival in HCC patients.

Drug insight: antiangiogenic therapies for gastrointestinal cancers--focus on monoclonal antibodies

Tumor angiogenesis is strongly induced by vascular endothelial growth factor (VEGF), which is overexpressed in most human gastrointestinal cancers. VEGF overexpression is known to be associated with poor prognosis and survival in patients with various solid tumors. The humanized monoclonal anti-VEGF antibody bevacizumab (Avastin, Genentech Inc., South San Francisco, CA) is a prototypic antiangiogenic compound, and has proven therapeutic benefit combined with conventional chemotherapy-namely, significantly improved progression-free survival in patients with metastatic colorectal cancer. Bevacizumab is the only anti-VEGF antibody that has been approved by the FDA and the European Medicines Agency for the treatment of metastatic colorectal cancer. Several ongoing clinical studies are evaluating the potential of bevacizumab therapy for other gastrointestinal cancers, in combination with chemotherapy, other targeted therapies and/or radiation. Soluble chimeric receptors, tyrosine kinase inhibitors, and monoclonal antibodies against VEGF and molecular targets in the integrin and Delta-like protein 4-Notch pathways are being developed. As tumors acquire resistance to anti-VEGF therapy, further development of antiangiogenic and vascular targets and therapy is warranted.

Systemic therapy for hepatocellular carcinoma: cytotoxic chemotherapy, targeted therapy and immunotherapy

Conventional cytotoxic chemotherapy has not provided clinical benefit or prolonged survival for patients with advanced HCC. This review summarizes the results of prospective clinical trials of several categories of systemic therapy, with emphasis on the more promising results from recent trials of biologically targeted therapeutic agents in HCC.