A preclinical and clinical review of aflibercept for the management of cancer

New developments in the second-line treatment of metastatic colorectal cancer: potential place in therapy

In this review article we discuss the evolution of second-line treatment options for patients with metastatic colorectal cancer (mCRC). The benefits of second-line chemotherapy have been established for some time, but in the last decade a number of trials have evaluated combinations of irinotecan- and oxaliplatin-based chemotherapy with molecular-targeted agents; e.g., vascular endothelial growth factor (VEGF)-targeting agents (bevacizumab, aflibercept), epidermal growth factor receptor antibodies (cetuximab, panitumumab), and tyrosine kinase inhibitors (vatalanib). Recent developments include the availability of the new VEGF-targeted agent aflibercept and the new concept of continuing bevacizumab after failure of first-line bevacizumab, which is likely to become a new treatment option in the second-line setting. Choosing the most appropriate second-line treatment regimen for mCRC patients remains a complex issue. All of the currently available molecular-targeted agents seem to be active even after patients have received a bevacizumab-based first-line regimen. Overall, the selection of second-line treatment for mCRC depends on several variables and should be determined taking into account the patient's performance and disease status.

Ziv-aflibercept in metastatic colorectal cancer

The combination of cytotoxic chemotherapy and antiangiogenic agents has become a conventional treatment option for patients with metastatic colorectal cancer. Ziv-aflibercept is a fusion protein which acts as a decoy receptor for vascular endothelial growth factor (VEGF)-A, VEGF-B, and placental growth factor (PlGF); it was approved in combination with 5-fluorouracil, leucovorin, and irinotecan (FOLFIRI) for the treatment of patients with metastatic colorectal cancer that is resistant to or has progressed after an oxaliplatin-containing fluoropyrimidine-based regimen. Herein we review the role of tumor angiogenesis as the rationale for antiangiogenic therapy, the clinical data associated with ziv-aflibercept, and its current role as a treatment option compared to other antiangiogenic agents, such as bevacizumab and regorafenib.

A phase II multicentre study of ziv-aflibercept in combination with cisplatin and pemetrexed in patients with previously untreated advanced/metastatic non-squamous non-small cell lung cancer

BACKGROUND

This study evaluated the efficacy and safety of ziv-aflibercept in combination with cisplatin and pemetrexed in non-small cell lung cancer (NSCLC).

METHODS

This single arm, multicentre phase II trial enrolled patients with previously untreated, locally advanced or metastatic non-squamous NSCLC. Patients received intravenous ziv-aflibercept 6 mg kg(-1), pemetrexed 500 mg m(-2), and cisplatin 75 mg m(-2), every 21 days for up to six cycles. Maintenance administration of ziv-aflibercept was to continue until disease progression, intolerable toxicity or other cause for withdrawal. The co-primary end points were objective response rate (ORR) and progression-free survival (PFS). Planned sample size was 72 patients.

RESULTS

The study was closed prematurely because of three confirmed and two suspected cases of reversible posterior leukoencephalopathy syndrome (RPLS). A total of 42 patients were enrolled. Median age was 61.5 years; 55% were male, 86% Caucasian and 50% had Eastern Cooperative Oncology Group performance status (ECOG PS)=0. A median of four cycles of ziv-aflibercept was administered. The most common treatment-emergent adverse events (TEAEs) of any grade were nausea (69%) and fatigue (67%), with hypertension (36%) as the most common grade 3/4 TEAE. Of the 38 evaluable patients, ORR was 26% and median PFS was 5 months.

CONCLUSION

Cases of RPLS had been observed in other studies in the ziv-aflibercept clinical development programme but the rate observed in this study was higher than previously observed. This might be related to declining renal function and/or hypertension. Although ORR and PFS were in accordance with most historical first-line NSCLC studies, this combination of ziv-aflibercept/cisplatin/pemetrexed will not be further explored in NSCLC.

[Recent update of molecular targeted therapy in pancreatic cancer]

Pancreatic ductal adenocarcinoma is one of the most dreaded malignancies and the 5th leading cause of cancer-related death in Korea. Late diagnosis and unfavorable response to both chemotherapy and radiotherapy result in exceptionally poor prognosis. Recently, the rapid advances of molecular biology allowed an in-depth understanding of pancreatic carcinogenesis, and there are many attempts to modulate signal pathway using specific targeted agent. However, the most of them have so far failed to improve survival significantly except erlotinib. The real challenge is now how these impressive advances of molecular biology could be successfully integrated into better clinical implications. Herein, we summarize the latest insights into the carcinogenesis, and their repercussions for novel targeted agents for pancreatic cancer, and provide a review of recent clinical trials using molecular targeted therapy.

Semaphorin 3E suppresses tumor cell death triggered by the plexin D1 dependence receptor in metastatic breast cancers

The semaphorin guidance molecules and their receptors, the plexins, are often inappropriately expressed in cancers. However, the signaling processes mediated by plexins in tumor cells are still poorly understood. Here, we demonstrate that the Semaphorin 3E (Sema3E) regulates tumor cell survival by suppressing an apoptotic pathway triggered by the Plexin D1 dependence receptor. In mouse models of breast cancer, a ligand trap that sequesters Sema3E inhibited tumor growth and reduced metastasis through a selective tumor cytocidal effect. We further showed that Plexin D1 triggers apoptosis via interaction with the orphan nuclear receptor NR4A1. These results define a critical role of Sema3E/Plexin D1 interaction in tumor resistance to apoptosis and suggest a therapeutic approach based on activation of a dependence receptor pathway.

Ziv-aflibercept: A novel angiogenesis inhibitor for the treatment of metastatic colorectal cancer

Purpose

The pharmacology, pharmacokinetics, clinical efficacy, safety, and administration of ziv-aflibercept in combination therapy for metastatic colorectal cancer (mCRC) are reviewed.

Summary

Ziv-aflibercept (Zaltrap, Regeneron Pharmaceuticals and sanofi-aventis) is a novel recombinant fusion protein that targets the angiogenesis signaling pathway of tumor cells by blocking vascular endothelial growth factor (VEGF) receptors that play a key role in tumor growth and metastasis; it is a more potent VEGF blocker than bevacizumab. Ziv-aflibercept is approved by the Food and Drug Administration for use in combination with fluorouracil, irinotecan, and leucovorin (the FOLFIRI regimen) for second-line treatment of patients with mCRC who have disease progression during first-line oxaliplatin-based chemotherapy. A Phase III trial demonstrated that relative to FOLFIRI therapy alone, the use of ziv-aflibercept was associated with significantly improved patient response, overall survival, and progression-free survival in patients with good performance status at baseline, including some who had received prior bevacizumab therapy. The most common grade 3 or 4 adverse effects associated with ziv-aflibercept use in clinical studies were neutropenia, hypertension, and diarrhea; the U.S. product labeling warns of potential hemorrhage and other treatment-related risks.

Conclusion

Current clinical data are insufficient to directly compare ziv-aflibercept and bevacizumab when used with standard combination chemotherapy as first- or second-line regimens for mCRC. The role of ziv-aflibercept is currently limited to the second-line setting in combination with irinotecan-based regimens in mCRC patients who have not received irinotecan previously. The role of ziv-aflibercept in chemotherapy for other tumor types is yet to be determined.

Combined blockade of HER2 and VEGF exerts greater growth inhibition of HER2-overexpressing gastric cancer xenografts than individual blockade

Gastric cancer overexpressing the human epidermal growth factor 2 (HER2) protein has a poor outcome, although a combination of chemotherapy and the anti-HER2 antibody trastuzumab has been approved for the treatment of advanced gastric cancer. Vascular endothelial growth factor (VEGF) expression in gastric cancer is correlated with recurrence and poor prognosis; however, the anti-VEGF antibody bevacizumab has shown limited efficacy against gastric cancer in clinical trials. In this study, we evaluated the antitumor effects of trastuzumab; VEGF-Trap binding to VEGF-A, VEGF-B and placental growth factor (PlGF); and a combination of trastuzumab and VEGF-Trap in a gastric cancer xenograft model. Although trastuzumab and VEGF-Trap each moderately inhibited tumor growth, the combination of these agents exerted greater inhibition compared with either agent alone. Immunohistochemical analyses indicated that the reduction in tumor growth was associated with decreased proliferation and increased apoptosis of tumor cells and decreased tumor vascular density. The combined treatment resulted in fewer proliferating tumor cells, more apoptotic cells and reduced tumor vascular density compared with treatment with trastuzumab or VEGF-Trap alone, indicating that trastuzumab and VEGF-Trap had additive inhibitory effects on the tumor growth and angiogenesis of the gastric cancer xenografts. These data suggest that trastuzumab in combination with VEGF-Trap may represent an effective approach to treating HER2-overexpressing gastric cancer.

Molecularly targeted drugs for metastatic colorectal cancer

The survival rate of patients with metastatic colorectal cancer (mCRC) has significantly improved with applications of molecularly targeted drugs, such as bevacizumab, and led to a substantial improvement in the overall survival rate. These drugs are capable of specifically targeting the inherent abnormal pathways in cancer cells, which are potentially less toxic than traditional nonselective chemotherapeutics. In this review, the recent clinical information about molecularly targeted therapy for mCRC is summarized, with specific focus on several of the US Food and Drug Administration-approved molecularly targeted drugs for the treatment of mCRC in the clinic. Progression-free and overall survival in patients with mCRC was improved greatly by the addition of bevacizumab and/or cetuximab to standard chemotherapy, in either first- or second-line treatment. Aflibercept has been used in combination with folinic acid (leucovorin)-fluorouracil-irinotecan (FOLFIRI) chemotherapy in mCRC patients and among patients with mCRC with wild-type KRAS, the outcomes were significantly improved by panitumumab in combination with folinic acid (leucovorin)-fluorouracil-oxaliplatin (FOLFOX) or FOLFIRI. Because of the new preliminary studies, it has been recommended that regorafenib be used with FOLFOX or FOLFIRI as first- or second-line treatment of mCRC chemotherapy. In summary, an era of new opportunities has been opened for treatment of mCRC and/or other malignancies, resulting from the discovery of new selective targeting drugs.

Angiogenesis inhibitors in cancer therapy: mechanistic perspective on classification and treatment rationales

Angiogenesis, a process of new blood vessel formation, is a prerequisite for tumour growth to supply the proliferating tumour with oxygen and nutrients. The angiogenic process may contribute to tumour progression, invasion and metastasis, and is generally accepted as an indicator of tumour prognosis. Therefore, targeting tumour angiogenesis has become of high clinical relevance. The current review aimed to highlight mechanistic details of anti-angiogenic therapies and how they relate to classification and treatment rationales. Angiogenesis inhibitors are classified into either direct inhibitors that target endothelial cells in the growing vasculature or indirect inhibitors that prevent the expression or block the activity of angiogenesis inducers. The latter class extends to include targeted therapy against oncogenes, conventional chemotherapeutic agents and drugs targeting other cells of the tumour micro-environment. Angiogenesis inhibitors may be used as either monotherapy or in combination with other anticancer drugs. In this context, many preclinical and clinical studies revealed higher therapeutic effectiveness of the combined treatments compared with individual treatments. The proper understanding of synergistic treatment modalities of angiogenesis inhibitors as well as their wide range of cellular targets could provide effective tools for future therapies of many types of cancer.

Bevacizumab and micrometastases: revisiting the preclinical and clinical rollercoaster

The use of bevacizumab, a monoclonal antibody against vascular endothelial growth factor (VEGF), in combination with standard therapeutic approaches, has offered clinical benefit for patients with advanced colorectal, breast, ovarian, renal, non small-cell lung cancer and glioblastoma. However, the strategy of administering bevacizumab until disease progression has been challenged by certain preclinical evidence, suggesting that prolonged exposure to anti-VEGF treatment may elicit an adaptive-evasive response, resulting in a more aggressive tumor phenotype. Moreover, the use of bevacizumab in adjuvant chemotherapeutic regimens has led to less promising results than expected. Despite our poor understanding of how bevacizumab acts in micrometastatic disease, numerous clinical trials (involving >20,000 cancer patients) are ongoing or are planned to test the therapeutic benefit in the adjuvant setting. The discrepancy of bevacizumab's efficiency in the two settings calls into question the validity of current strategies that use similar treatment regimens for early and advanced diseases. Herein, we review the mechanisms of bevacizumab activity in the macro- as compared to the micrometastatic environment and discuss possible alternative strategies in the adjuvant setting that might spur attention for future clinical trials. Rather than providing an encyclopedic survey of the literature, we highlight exemplary principles.

Tumor markers in colorectal cancer, gastric cancer and gastrointestinal stromal cancers: European group on tumor markers 2014 guidelines update

Biomarkers currently play an important role in the detection and management of patients with several different types of gastrointestinal cancer, especially colorectal, gastric, gastro-oesophageal junction (GOJ) adenocarcinomas and gastrointestinal stromal tumors (GISTs). The aim of this article is to provide updated and evidence-based guidelines for the use of biomarkers in the different gastrointestinal malignancies. Recommended biomarkers for colorectal cancer include an immunochemical-based fecal occult blood test in screening asymptomatic subjects ≥50 years of age for neoplasia, serial CEA levels in postoperative surveillance of stage II and III patients who may be candidates for surgical resection or systemic therapy in the event of distant metastasis occurring, K-RAS mutation status for identifying patients with advanced disease likely to benefit from anti-EGFR therapeutic antibodies and microsatellite instability testing as a first-line screen for subjects with Lynch syndrome. In advanced gastric or GOJ cancers, measurement of HER2 is recommended in selecting patients for treatment with trastuzumab. For patients with suspected GIST, determination of KIT protein should be used as a diagnostic aid, while KIT mutational analysis may be used for treatment planning in patients with diagnosed GISTs.

Monoclonal antibodies and other targeted therapies for pancreatic cancer

Pancreatic cancer continues to be a challenging disease to treat because of its aggressive nature, advanced stage at the time of diagnosis, and limited treatment options that are available. Traditional cytotoxic chemotherapy provides modest benefit to patients with pancreatic adenocarcinoma. Recently, a FOLFIRINOX regimen revealed improved response in overall and progression-free survival over single-agent gemcitabine in metastatic pancreatic cancer, but there is still much needed advancement in the systemic treatment of pancreatic cancer. There is a growing interest in the development of novel agents, while our understanding of molecular pathogenesis of pancreatic adenocarcinoma continues to expand. With identification of various molecular pathways in pancreatic cancer tumorigenesis, potential targets for drug development have been pursued with the use of monoclonal antibodies and small-molecule inhibitors. Although preclinical studies with multiple targeted therapies demonstrated encouraging results in pancreatic cancer, only erlotinib, an epidermal growth factor receptor inhibitor, showed a marginal survival benefit in a phase III clinical trial, when combined with gemcitabine. As further signaling pathways and their importance in pancreatic cancer tumorigenesis are better understood, further clinical trials will need to be designed to study these targeted agents as single agents, in combination with other novel agents or in combination with cytotoxic chemotherapy. In this review, we present the current knowledge on targeted therapy in pancreatic adenocarcinoma and its application in clinical practice.

Compartment model predicts VEGF secretion and investigates the effects of VEGF trap in tumor-bearing mice

Angiogenesis, the formation of new blood vessels from existing vasculature, is important in tumor growth and metastasis. A key regulator of angiogenesis is vascular endothelial growth factor (VEGF), which has been targeted in numerous anti-angiogenic therapies aimed at inhibiting tumor angiogenesis. Systems biology approaches, including computational modeling, are useful for understanding this complex biological process and can aid in the development of novel and effective therapeutics that target the VEGF family of proteins and receptors. We have developed a computational model of VEGF transport and kinetics in the tumor-bearing mouse, which includes three-compartments: normal tissue, blood, and tumor. The model simulates human tumor xenografts and includes human (VEGF121 and VEGF165) and mouse (VEGF120 and VEGF164) isoforms. The model incorporates molecular interactions between these VEGF isoforms and receptors (VEGFR1 and VEGFR2), as well as co-receptors (NRP1 and NRP2). We also include important soluble factors: soluble VEGFR1 (sFlt-1) and α-2-macroglobulin. The model accounts for transport via macromolecular transendothelial permeability, lymphatic flow, and plasma clearance. We have fit the model to available in vivo experimental data on the plasma concentration of free VEGF Trap and VEGF Trap bound to mouse and human VEGF in order to estimate the rates at which parenchymal cells (myocytes and tumor cells) and endothelial cells secrete VEGF. Interestingly, the predicted tumor VEGF secretion rates are significantly lower (0.007-0.023 molecules/cell/s, depending on the tumor microenvironment) than most reported in vitro measurements (0.03-2.65 molecules/cell/s). The optimized model is used to investigate the interstitial and plasma VEGF concentrations and the effect of the VEGF-neutralizing agent, VEGF Trap (aflibercept). This work complements experimental studies performed in mice and provides a framework with which to examine the effects of anti-VEGF agents, aiding in the optimization of such anti-angiogenic therapeutics as well as analysis of clinical data. The model predictions also have implications for biomarker discovery with anti-angiogenic therapies.

Update on antiangiogenic therapy in colorectal cancer: aflibercept and regorafenib

Angiogenesis plays an important role in colorectal carcinogenesis and approaches targeting the vascular growth factor receptor (VEGF) signaling such as bevacizumab yielded significant survival improvement for metastatic colorectal cancer patients. Recent evidence demonstrated the benefit of continuing angiogenic suppression after first-progression following bevacizumab-containing cytotoxic regimen though no benefit was observed with the use of bevacizumab in adjuvant setting. Aflibercept, a soluble fusion protein with high affinity for VEGF-A, -B and PlGF, administered in combination with irinotecan-containing regimen improved the survival of metastatic colorectal cancer patients in second-line setting (VELOUR trial). Regorafenib, a small molecule multikinase inhibitor against various pro-angiogenic and -proliferation targets, improved the survival of metastatic colorectal cancer patients who had progressed on all standard therapy. These developments had renewed enthusiasm in the field and the role of aflibercept and regorafenib in other treatment settings will continue to be defined by on-going and future clinical trials. As other anti-angiogenic approaches are being tested clinically, other novel non-angiogenic targets deserve to be evaluated in our effort to improve the outcome of colorectal cancer patients.

Production of recombinant immunotherapeutics for anticancer treatment: the role of bioengineering

Cancer is one of the most important health problems because many cases are difficult to prevent. Cancer still has unknown mechanisms of pathogenesis, and its capacity to produce temporary or permanent damage, besides death, is very high. Although many anticancer therapies are available, finding a cure for cancer continues to be a difficult task. Thus, many efforts have been made to develop more effective treatments, such as immunotherapy based on a new class of tumor-specific products that are produced using recombinant DNA technology. These recombinant products are used with the main objectives of killing the tumor and stimulating immune cells to respond to the cancer cells. The principal recombinant products in anticancer therapy are immunostimulants, vaccines, antibodies, immunotoxins and fusion proteins. This review focuses on the general aspects of these genetically engineered products, their clinical performance, current advances and future prospects for this type of anticancer therapy.

Current and Novel Treatment Options for Metastatic Colorectal Cancer: Emphasis on Aflibercept

Worldwide, colorectal cancer (CRC) is the third most frequently diagnosed cancer in men and the second in women. Metastatic disease develops in more than half of the patients and carries a poor prognosis. Over the past three decades, significant advances have been made in the treatment of metastatic colorectal cancer (mCRC). The development of new cytotoxic agents and the incorporation of target-specific agents in first-, second-, third-, and nowadays even fourth-line treatment has prolonged median overall survival up to 24–28 months. However, 5-year survival rates remain disappointingly low. This review summarizes the currently available cytotoxic treatment options for mCRC, and highlights the further emerging role of vascular endothelial growth factor (VEGF)-inhibiting strategies, emphasizing the role of aflibercept. Aflibercept is a recombinant fusion protein with high VEGF affinity, and is the second antiangiogenic agent to obtain registration in the treatment of mCRC.

Aflibercept

Aflibercept, an intravenously administered anti-VEGF and antiplacental growth factor (PlGF) agent, has recently been approved by the U.S. Food and Drug Administration in combination with 5-fluorouracil, leucovorin, and irinotecan (FOLFIRI) for the treatment of patients with metastatic colorectal cancer who have previously received an oxaliplatin-containing chemotherapy regimen. In the phase III VELOUR trial, aflibercept plus FOLFIRI statistically significantly prolonged both progression-free survival (PFS; median PFS for the aflibercept plus FOLFIRI arm was 6.90 vs. 4.67 months for the placebo-plus-FOLFIRI arm) and overall survival (median overall survival for the aflibercept-plus-FOLFIRI arm was 13.50 vs. 12.06 months for the placebo plus FOLFIRI arm), but grade 3 or 4 adverse events were more common with the addition of aflibercept. However, the addition of aflibercept to 5-fluorouracil, leucovorin, and oxaliplatin (mFOLFOX6) in the phase II AFFIRM trial of first-line treatment of mCRC failed to improve PFS or response rate. As a decoy VEGF receptor, aflibercept (VEGF-Trap) has binding affinity for VEGF-A, VEGF-B, PlGF-1, and PlGF-2, and this is a mechanism of significant interest. Optimal strategies for incorporating aflibercept into treatment regimens that include other anti-VEGF and cytotoxic chemotherapeutic agents, as well as development of predictive biomarkers for treatment response, have yet to be defined.

Systemic cytotoxic and biological therapies of colorectal liver metastases: expert consensus statement

Systemic therapy for colorectal cancer liver metastases (CRLM) has undergone significant development in the past 15 years. Therapy regimens consisting of combinations of cytotoxic chemotherapeutic agents have demonstrated greater efficacy and contributed to a significant survival improvement. As the majority of patients who undergo resection for liver-only CRLM are at risk of disease recurrence and cancer-related death, combining resection with systemic therapy appears sensible. However, trial-based evidence is sparse to support this concept. Peri-operative FOLFOX has demonstrated a progression-free survival benefit in a single Phase III trial; the safety of chemotherapy and subsequent operations was acceptable and only a few patients showed initial progression. Chemotherapy-associated liver injury (CALI), including sinusoidal obstruction syndrome and steatohepatitis, has been observed after cytotoxic therapy, and should have implications for chemotherapy plans prior to hepatectomy. In general, pre-operative chemotherapy should not extend beyond 3 months. For patients with unresectable liver-only CRLM, a response to chemotherapy could establish resectability and should be considered an initial treatment goal. In patients with unresectable CRLM, oxaliplatin- or irinotecan-containing combinations represent the standard options, although single-agent choices may be appropriate for individual patients. The addition of bevacizumab carries the potential for a greater response and possibly for reduced CALI risks. In tumours without K-ras mutations, anti-epidermal growth factor receptor (EGFR) agents are also reasonable choices for a greater response and improved survival outcomes. It is crucial that all systemic CRLM treatment decisions include proper definitions of treatment goals and endpoints, and are derived based on appropriate multidisciplinary considerations for other potentially applicable local or regional modalities.

Ziv-aflibercept: binding to more than VEGF-A--does more matter?

The VELOUR and VITAL studies recently demonstrated ziv-aflibercept improved overall survival in patients with metastatic colorectal cancer (mCRC), including those previously treated with bevacizumab, but did not improve overall survival in non-small-cell lung cancer. Thus, VEGF-directed agents might be useful throughout the continuum of care in mCRC, but biomarkers are needed to identify patients likely to benefit.

Tumor stroma as targets for cancer therapy

Cancer is not only composed malignant epithelial component but also stromal components such as fibroblasts, endothelial cells, and inflammatory cells, by which an appropriate tumor microenvironment (TME) is formed to promote tumorigenesis, progression, and metastasis. As the most abundant component in the TME, cancer-associated fibroblasts (CAFs) are involved in multifaceted mechanistic details including remodeling the extracellular matrix, suppressing immune responses, and secreting growth factors and cytokines that mediate signaling pathways to extensively affect tumor cell growth and invasiveness, differentiation, angiogenesis, and chronic inflammatory milieu. Today, more and more therapeutic strategies are purposefully designed to target the TME as well as tumor cells. This review will focus on the role of CAFs in tumor development and the novel strategies to target this component to inhibit the tumor growth.

Angiogenesis in metastatic colorectal cancer and the benefits of targeted therapy

The diverse pathways and molecules involved in angiogenesis, the formation of new blood vessels, have been targeted for the treatment of colorectal and other cancers. Vascular endothelial growth factor (VEGF)-A binding to VEGF receptor (VEGFR)-2 is believed to be the key signaling pathway mediating angiogenesis. Other VEGF pathways involved in angiogenesis include VEGF-A, VEGF-B, and placental growth factor binding to VEGFR-1, and VEGF-C and VEGF-D binding to VEGFR-2 and VEGFR-3. VEGF signaling also intersects with other pathways, including angiopoietin/Tie, Notch, hypoxia-inducible factor, and integrin pathways. The roles of these pathways in tumor angiogenesis and in various human cancers will be explored in this article. In addition, preclinical and clinical data on bevacizumab, aflibercept (known as ziv-aflibercept in the US), and investigational antiangiogenic agents in development for the treatment of colorectal and other cancers will be reviewed.

Controlling escape from angiogenesis inhibitors

Selective inhibition of vascular endothelial growth factor (VEGF) increases the efficacy of chemotherapy and has beneficial effects on multiple advanced cancers, but response is often limited and the disease eventually progresses. Changes in the tumour microenvironment--hypoxia among them--that result from vascular pruning, suppressed angiogenesis and other consequences of VEGF inhibition can promote escape and tumour progression. New therapeutic approaches that target pathways that are involved in the escape mechanisms add the benefits of blocking tumour progression to those of slowing tumour growth by inhibiting angiogenesis.

Aflibercept in Pediatric Solid Tumors: Moving Beyond the Trap

Angiogenesis plays a pivotal role in the growth and metastasis of adult and pediatric solid tumors. Clinical investigation of angiogenesis inhibitors is currently under way for childhood cancers. While the pediatric study of aflibercept provides a proof-of-principle, challenges remain in developing clinical endpoints and biomarkers of angiogenesis for pediatric trials. Clin Cancer Res; 18(18); 4868–71. ©2012 AACR.

Emerging treatment options for management of malignant ascites in patients with ovarian cancer

Malignant ascites affects approximately 10% of patients with recurrent epithelial ovarian cancer and is associated with troublesome symptoms, including abdominal pressure and distension, dyspnea, bloating, pelvic pain, and bowel/bladder dysfunction. To date, no effective therapy has been identified for the treatment of malignant ascites in patients with recurrent, advanced ovarian cancer. In this article, we discuss currently existing options for the treatment of ascites associated with ovarian cancer, and review the literature as it pertains to novel, targeted therapies. Specifically, preclinical and clinical trials exploring the use of the antiangiogenic agents, bevacizumab and vascular endothelial growth factor-trap, as well as the nonangiogenic agent, catumaxomab, will be reviewed. Despite current limitations in treatment, knowledge regarding management options in the palliation of ascites is critical to practicing physicians. Ultimately, as with all novel therapies, symptom relief and treatment goals must be weighed against patient discomfort and potentially significant adverse events.

Targeting the vasculature of visceral tumors: novel insights and treatment perspectives

BACKGROUND

Angiogenesis, the formation of new blood vessels from the endothelium of the existing vasculature, describes a crucial process in tumor growth, disease progression, and metastasis. Therefore, the upcoming strategy of inhibiting tumor angiogenesis has generated different treatment modalities, which have been transferred into clinical practice in recent years. Currently, this concept is applied to target the vasculature of different visceral tumors and intensive clinical research has just started.

MATERIALS AND METHODS

This review summarizes the modifications of systemic treatment of visceral tumors by targeting the vasculature in the past years. Moreover, novel targets and treatment strategies will be discussed to evaluate future directions.

RESULTS

Leading antiangiogenic drugs combined with systemic chemotherapy have been applied with increasing success during the last years. Therefore, the concept of combining vascular targeting agents with established chemotherapeutic regimens has been increasingly adopted into the therapies of different visceral tumors.

CONCLUSION

Targeting the vasculature of visceral tumors in combination with established standard tumor therapies includes major clinical potential for future therapy concepts.